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StrBegin

Description

Pointer to the first character of the string. Equivalent to str->data.

Parameters

Name Direction Description
str in String to query.

Usage example (Cross-references)

Usage examples (Cross-references)
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: file_open((Zstr)StrBegin((Str *)(path)), (mode)),                                                       \
            Zstr: file_open((Zstr)(path), (mode)),                                                                         \
            char *: file_open((Zstr)(path), (mode))                                                                        \
            Buf *: _Generic(                                                                                               \
                     (path),                                                                                               \
                    Str *: file_read_and_close_to_buf((Zstr)StrBegin((Str *)(path)), (Buf *)(out)),                        \
                    Zstr: file_read_and_close_to_buf((Zstr)(path), (Buf *)(out)),                                          \
                    char *: file_read_and_close_to_buf((Zstr)(path), (Buf *)(out))                                         \
            Str *: _Generic(                                                                                               \
                     (path),                                                                                               \
                    Str *: file_read_and_close_to_str((Zstr)StrBegin((Str *)(path)), (Str *)(out)),                        \
                    Zstr: file_read_and_close_to_str((Zstr)(path), (Str *)(out)),                                          \
                    char *: file_read_and_close_to_str((Zstr)(path), (Str *)(out))                                         \
            Buf *: _Generic(                                                                                               \
                     (path),                                                                                               \
                    Str *: file_write_and_close_from_buf((Zstr)StrBegin((Str *)(path)), (const Buf *)(container)),         \
                    Zstr: file_write_and_close_from_buf((Zstr)(path), (const Buf *)(container)),                           \
                    char *: file_write_and_close_from_buf((Zstr)(path), (const Buf *)(container))                          \
            Str *: _Generic(                                                                                               \
                     (path),                                                                                               \
                    Str *: file_write_and_close_from_str((Zstr)StrBegin((Str *)(path)), (const Str *)(container)),         \
                    Zstr: file_write_and_close_from_str((Zstr)(path), (const Str *)(container)),                           \
                    char *: file_write_and_close_from_str((Zstr)(path), (const Str *)(container))                          \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: file_write_and_close_from_bytes((Zstr)StrBegin((Str *)(path)), (buf), (n)),                             \
            Zstr: file_write_and_close_from_bytes((Zstr)(path), (buf), (n)),                                               \
            char *: file_write_and_close_from_bytes((Zstr)(path), (buf), (n))                                              \
            Str           UNPL(m)         = StrInit(&UNPL(log_alloc));                                                     \
            StrAppendFmt(&UNPL(m), __VA_ARGS__);                                                                           \
            LogWrite(LOG_MESSAGE_TYPE_FATAL, __func__, __LINE__, StrBegin(&UNPL(m)));                                      \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
            Str           UNPL(m)         = StrInit(&UNPL(log_alloc));                                                     \
            StrAppendFmt(&UNPL(m), __VA_ARGS__);                                                                           \
            LogWrite(LOG_MESSAGE_TYPE_ERROR, __func__, __LINE__, StrBegin(&UNPL(m)));                                      \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
            Str           UNPL(m)         = StrInit(&UNPL(log_alloc));                                                     \
            StrAppendFmt(&UNPL(m), __VA_ARGS__);                                                                           \
            LogWrite(LOG_MESSAGE_TYPE_INFO, __func__, __LINE__, StrBegin(&UNPL(m)));                                       \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
                StrAppendFmt(&UNPL(m), " : {}", UNPL(syserr));                                                             \
            }                                                                                                              \
            LogWrite(LOG_MESSAGE_TYPE_FATAL, __func__, __LINE__, StrBegin(&UNPL(m)));                                      \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
                StrAppendFmt(&UNPL(m), " : {}", UNPL(syserr));                                                             \
            }                                                                                                              \
            LogWrite(LOG_MESSAGE_TYPE_ERROR, __func__, __LINE__, StrBegin(&UNPL(m)));                                      \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
                StrAppendFmt(&UNPL(m), " : {}", UNPL(syserr));                                                             \
            }                                                                                                              \
            LogWrite(LOG_MESSAGE_TYPE_INFO, __func__, __LINE__, StrBegin(&UNPL(m)));                                       \
            StrDeinit(&UNPL(m));                                                                                           \
            HeapAllocatorDeinit(&UNPL(log_alloc));                                                                         \
    ///
    #define StrInitFromStr(...)      OVERLOAD(StrInitFromStr, __VA_ARGS__)
    #define StrInitFromStr_1(str)    StrInitFromCstr_2(StrBegin(str), StrLen(str))
    #define StrInitFromStr_2(str, a) StrInitFromCstr_3(StrBegin(str), StrLen(str), (a))
    #define StrInitFromStr(...)      OVERLOAD(StrInitFromStr, __VA_ARGS__)
    #define StrInitFromStr_1(str)    StrInitFromCstr_2(StrBegin(str), StrLen(str))
    #define StrInitFromStr_2(str, a) StrInitFromCstr_3(StrBegin(str), StrLen(str), (a))
    
    ///
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_get_contents((Zstr)StrBegin((Str *)(path)), MisraScope),                                            \
            Zstr: dir_get_contents((Zstr)(path), MisraScope),                                                              \
            char *: dir_get_contents((Zstr)(path), MisraScope)                                                             \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_get_contents((Zstr)StrBegin((Str *)(path)), ALLOCATOR_OF(alloc)),                                   \
            Zstr: dir_get_contents((Zstr)(path), ALLOCATOR_OF(alloc)),                                                     \
            char *: dir_get_contents((Zstr)(path), ALLOCATOR_OF(alloc))                                                    \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: file_get_size((Zstr)StrBegin((Str *)(path))),                                                           \
            Zstr: file_get_size((Zstr)(path)),                                                                             \
            char *: file_get_size((Zstr)(path))                                                                            \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: file_remove((Zstr)StrBegin((Str *)(path))),                                                             \
            Zstr: file_remove((Zstr)(path)),                                                                               \
            char *: file_remove((Zstr)(path))                                                                              \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_remove((Zstr)StrBegin((Str *)(path))),                                                              \
            Zstr: dir_remove((Zstr)(path)),                                                                                \
            char *: dir_remove((Zstr)(path))                                                                               \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_create((Zstr)StrBegin((Str *)(path))),                                                              \
            Zstr: dir_create((Zstr)(path)),                                                                                \
            char *: dir_create((Zstr)(path))                                                                               \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_create_all((Zstr)StrBegin((Str *)(path))),                                                          \
            Zstr: dir_create_all((Zstr)(path)),                                                                            \
            char *: dir_create_all((Zstr)(path))                                                                           \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: dir_remove_all((Zstr)StrBegin((Str *)(path))),                                                          \
            Zstr: dir_remove_all((Zstr)(path)),                                                                            \
            char *: dir_remove_all((Zstr)(path))                                                                           \
            Str UNPL(buf) = StrInit();                                                                                     \
            ProcReadFromStdout((p), &UNPL(buf));                                                                           \
            Zstr UNPL(in) = StrBegin(&UNPL(buf));                                                                          \
            StrReadFmt(UNPL(in), __VA_ARGS__);                                                                             \
            StrDeinit(&UNPL(buf));                                                                                         \
            Str UNPL(buf) = StrInit();                                                                                     \
            ProcReadFromStderr((p), &UNPL(buf));                                                                           \
            Zstr UNPL(in) = StrBegin(&UNPL(buf));                                                                          \
            StrReadFmt(UNPL(in), __VA_ARGS__);                                                                             \
            StrDeinit(&UNPL(buf));                                                                                         \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: pdb_open((out), (Zstr)StrBegin((Str *)(path)), MisraScope),                                             \
            Zstr: pdb_open((out), (Zstr)(path), MisraScope),                                                               \
            char *: pdb_open((out), (Zstr)(path), MisraScope)                                                              \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: pdb_open((out), (Zstr)StrBegin((Str *)(path)), ALLOCATOR_OF(alloc)),                                    \
            Zstr: pdb_open((out), (Zstr)(path), ALLOCATOR_OF(alloc)),                                                      \
            char *: pdb_open((out), (Zstr)(path), ALLOCATOR_OF(alloc))                                                     \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: elf_open((out), (Zstr)StrBegin((Str *)(path)), MisraScope),                                             \
            Zstr: elf_open((out), (Zstr)(path), MisraScope),                                                               \
            char *: elf_open((out), (Zstr)(path), MisraScope)                                                              \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: elf_open((out), (Zstr)StrBegin((Str *)(path)), ALLOCATOR_OF(alloc)),                                    \
            Zstr: elf_open((out), (Zstr)(path), ALLOCATOR_OF(alloc)),                                                      \
            char *: elf_open((out), (Zstr)(path), ALLOCATOR_OF(alloc))                                                     \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: pe_open((out), (Zstr)StrBegin((Str *)(path)), MisraScope),                                              \
            Zstr: pe_open((out), (Zstr)(path), MisraScope),                                                                \
            char *: pe_open((out), (Zstr)(path), MisraScope)                                                               \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: pe_open((out), (Zstr)StrBegin((Str *)(path)), ALLOCATOR_OF(alloc)),                                     \
            Zstr: pe_open((out), (Zstr)(path), ALLOCATOR_OF(alloc)),                                                       \
            char *: pe_open((out), (Zstr)(path), ALLOCATOR_OF(alloc))                                                      \
            const Str *UNPL(jw_s)   = &(s);                                                                                \
            u64        UNPL(jw_len) = StrLen(UNPL(jw_s));                                                                  \
            StrAppendFmt(&(j), "\"{}\"", UNPL(jw_len) ? (Zstr)StrBegin(UNPL(jw_s)) : (Zstr) "");                           \
        } while (0)
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: macho_open((out), (Zstr)StrBegin((Str *)(path)), MisraScope),                                           \
            Zstr: macho_open((out), (Zstr)(path), MisraScope),                                                             \
            char *: macho_open((out), (Zstr)(path), MisraScope)                                                            \
        _Generic(                                                                                                          \
            (path),                                                                                                        \
            Str *: macho_open((out), (Zstr)StrBegin((Str *)(path)), ALLOCATOR_OF(alloc)),                                  \
            Zstr: macho_open((out), (Zstr)(path), ALLOCATOR_OF(alloc)),                                                    \
            char *: macho_open((out), (Zstr)(path), ALLOCATOR_OF(alloc))                                                   \
        macho_find_section(                                                                                                \
            (self),                                                                                                        \
            _Generic((segment), Str *: (Zstr)StrBegin((Str *)(segment)), Zstr: (Zstr)(segment), char *: (Zstr)(segment)),  \
            _Generic((section), Str *: (Zstr)StrBegin((Str *)(section)), Zstr: (Zstr)(section), char *: (Zstr)(section))   \
        )
            (self),                                                                                                        \
            _Generic((segment), Str *: (Zstr)StrBegin((Str *)(segment)), Zstr: (Zstr)(segment), char *: (Zstr)(segment)),  \
            _Generic((section), Str *: (Zstr)StrBegin((Str *)(section)), Zstr: (Zstr)(section), char *: (Zstr)(section))   \
        )
            (src),                                                                                                         \
            File *: proc_maps_load_from_file((out), (File *)(src), MisraScope),                                            \
            Str *: proc_maps_load_from_bytes((out), (const u8 *)StrBegin((Str *)(src)), StrLen((Str *)(src)), MisraScope), \
            Buf *: proc_maps_load_from_bytes((out), BufData((Buf *)(src)), BufLength((Buf *)(src)), MisraScope)            \
        )
            Str *: proc_maps_load_from_bytes(                                                                              \
                     (out),                                                                                                \
                     (const u8 *)StrBegin((Str *)(src)),                                                                   \
                     StrLen((Str *)(src)),                                                                                 \
                     ALLOCATOR_OF(alloc)                                                                                   \
        // empty fresh Str.
        Str copy = (StrLen(src) == 0) ? StrInit((Allocator *)alloc) :
                                        StrInitFromCstr(StrBegin(src), StrLen(src), (Allocator *)alloc);
        *(Str *)dst_ptr = copy;
        return true;
    
        File out = (type == LOG_MESSAGE_TYPE_INFO) ? FileFromFd(1) : FileFromFd(2);
        (void)FileWrite(&out, StrBegin(&full), StrLen(&full));
    
    #if FEATURE_SYS_BACKTRACE && (!defined(LOG_NO_BACKTRACE) || !LOG_NO_BACKTRACE)
            // boundary; pass at the call site, no intermediate variable.
            FormatStackTrace(&trace, frames, n, ALLOCATOR_OF(&h));
            (void)FileWrite(&out, StrBegin(&trace), StrLen(&trace));
            StrDeinit(&trace);
        }
                    break;
                }
                char *data = StrBegin(&flagbuf);
                MemCopy(data, tok, n);
                data[n] = '\0';
            bool iter_ok = false;
            StrInitStack(buf, 3) {
                char *data = StrBegin(&buf);
                data[0]    = '-';
                data[1]    = *p;
                        } decision = BUNDLE_REJECT;
                        StrInitStack(two, 3) {
                            char *data = StrBegin(&two);
                            data[0]    = '-';
                            data[1]    = tok[1];
                ok = false;
            } else if (StrLen(&tmp)) {
                MemCopy(StrBegin(o) + offset, StrBegin(&tmp), StrLen(&tmp));
            }
        }
        }
    
        if (ok && StrLen(&out) > 0 && FileWrite(stream, StrBegin(&out), StrLen(&out)) != (i64)StrLen(&out)) {
            LOG_ERROR("Failed to write formatted output");
            ok = false;
                bool    spec_ok  = false;
                StrInitStack(spec_buf, 32) {
                    char *data = StrBegin(&spec_buf);
                    MemCopy(data, start, spec_len);
                    data[spec_len] = '\0';
                ok = false;
            } else if (StrLen(&tmp)) {
                MemCopy(BufData(out) + offset, StrBegin(&tmp), StrLen(&tmp));
            }
        }
                StrPushBackR(&buffer, buf_byte);
            }
            str_read_fmt(StrBegin(&buffer), fmtstr, argv, argc);
        } else {
            // Remember the start position so we can rewind after a parse
            if (file_len > 0) {
                StrReserve(&buffer, (u64)file_len);
                i64 got = FileRead(file, StrBegin(&buffer), (u64)file_len);
                if (got < 0) {
                    LOG_ERROR("FileRead failed during f_read_fmt");
    
            if (StrLen(&buffer)) {
                Zstr new_pos = str_read_fmt(StrBegin(&buffer), fmtstr, argv, argc);
                if (!new_pos) {
                    LOG_ERROR("Parse failed, rolling back...");
                } else {
                    // Advance the channel position past the bytes we consumed.
                    i64 consumed = (i64)(new_pos - StrBegin(&buffer));
                    (void)FileSeek(file, cur_pos + consumed, FILE_SEEK_SET);
                }
        bool ok = true;
        StrInitStack(digits, 32) {
            char *data        = StrBegin(&digits);
            u32   digit_count = 0;
    
        {
            Zstr body   = StrBegin(&canonical);
            Zstr dot    = NULL;
            u64  prefix = 0;
            result = StrInit(alloc);
    
            if (StrBegin(&canonical)[0] == '-') {
                if (!StrPushBackR(&result, '-')) {
                    goto fail;
    
        exponent = value->exponent + (i64)StrLen(&digits) - 1;
        if (!StrPushBackR(&result, StrBegin(&digits)[0])) {
            goto fail;
        }
            for (u64 i = 0; i < frac_digits; i++) {
                if (i + 1 < StrLen(&digits)) {
                    if (!StrPushBackR(&result, StrBegin(&digits)[i + 1])) {
                        goto fail;
                    }
    
                if (fmt_info->flags & FMT_FLAG_CHAR) {
                    if (!write_char_internal(o, fmt_info->flags, (Zstr)StrBegin(s), len)) {
                        return false;
                    }
    // the slice is handed to the typed `StrToU64` / `StrToI64` parser.
    static bool is_valid_numeric_string(const Str *str, bool allow_float) {
        if (!str || !StrBegin(str))
            return false;
    
        size        len  = StrLen(str);
        const char *data = StrBegin(str);
    
        if (len == 0)
        // a malformed integer; the parser proper would accept the leading
        // '0' and silently lose the prefix, so reject early.
        if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&
            (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||
             StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {
        // '0' and silently lose the prefix, so reject early.
        if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&
            (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||
             StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {
            LOG_ERROR("Incomplete number format");
        if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&
            (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||
             StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {
            LOG_ERROR("Incomplete number format");
            StrDeinit(&temp);
            Str  temp  = StrInitFromCstr(start, pos, &scratch);                                                            \
                                                                                                                           \
            if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&                                                         \
                (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||                    \
                 StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {                   \
                                                                                                                           \
            if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&                                                         \
                (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||                    \
                 StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {                   \
                LOG_ERROR("Incomplete number format");                                                                     \
            if (StrLen(&temp) == 2 && StrBegin(&temp)[0] == '0' &&                                                         \
                (StrBegin(&temp)[1] == 'x' || StrBegin(&temp)[1] == 'X' || StrBegin(&temp)[1] == 'b' ||                    \
                 StrBegin(&temp)[1] == 'B' || StrBegin(&temp)[1] == 'o' || StrBegin(&temp)[1] == 'O')) {                   \
                LOG_ERROR("Incomplete number format");                                                                     \
                StrDeinit(&temp);                                                                                          \
        // the caller owns and may mutate the returned buffer. ZstrDupN's Zstr
        // return is just the project-wide convention for fresh allocations.
        result = (char *)ZstrDupN(StrBegin(&temp), StrLen(&temp), allocator_ptr);
        if (!result) {
            LOG_ERROR("Failed to allocate memory for string");
        );
    
        *bv = BitVecFromStr(StrBegin(&bin_str), BitVecAllocator(bv));
    
        StrDeinit(&bin_str);
        Str  temp   = StrInitFromCstr(start, StrIterIndex(&si) - StrIterIndex(&saved), IntAllocator(value));
        Int  parsed = IntInit(IntAllocator(value));
        bool ok     = IntTryFromStrRadix(&parsed, StrBegin(&temp), radix);
    
        if (!ok) {
        StrDeinit(&temp);
        temp = StrInitFromCstr(start, token_len, FloatAllocator(value));
        if (!FloatTryFromStr(&parsed, StrBegin(&temp))) {
            StrDeinit(&temp);
            FloatDeinit(&parsed);
    
        min = StrLen(a) < StrLen(b) ? StrLen(a) : StrLen(b);
        cmp = MemCompare(StrBegin(a), StrBegin(b), min);
    
        if (cmp != 0) {
    i32 str_cmp_zstr(const Str *s, Zstr other) {
        ValidateStr(s);
        return ZstrCompare(StrBegin(s), other);
    }
    i32 str_cmp_cstr(const Str *s, Zstr other, size other_len) {
        ValidateStr(s);
        return ZstrCompareN(StrBegin(s), other, other_len);
    }
        ValidateStr(s);
        ValidateStr(other);
        return ZstrCompareIgnoreCase(StrBegin(s), StrBegin(other));
    }
    i32 str_cmp_zstr_ignore_case(const Str *s, Zstr other) {
        ValidateStr(s);
        return ZstrCompareIgnoreCase(StrBegin(s), other);
    }
    i32 str_cmp_cstr_ignore_case(const Str *s, Zstr other, size other_len) {
        ValidateStr(s);
        return ZstrCompareNIgnoreCase(StrBegin(s), other, other_len);
    }
    Zstr str_find_cstr(const Str *s, Zstr key, size key_len) {
        ValidateStr(s);
        return ZstrFindSubstringN(StrBegin(s), key, key_len);
    }
    Zstr str_find_zstr(const Str *s, Zstr key) {
        ValidateStr(s);
        return ZstrFindSubstring(StrBegin(s), key);
    }
        ValidateStr(s);
        ValidateStr(key);
        return ZstrFindSubstringN(StrBegin(s), StrBegin(key), StrLen(key));
    }
            bool ok = true;
            StrInitStack(buffer, 65) {
                char *data = StrBegin(&buffer);
                size  pos  = 0;
                bool ok = true;
                StrInitStack(exp_buf, 8) {
                    char *data    = StrBegin(&exp_buf);
                    size  exp_pos = 0;
                    while (exp > 0) {
                bool ok = true;
                StrInitStack(int_buf, 32) {
                    char *data    = StrBegin(&int_buf);
                    size  int_pos = 0;
                    while (int_part > 0) {
        }
    
        return int_try_from_str_radix_impl(out, StrBegin(decimal), StrLen(decimal), start, 10, true);
    }
        }
    
        return int_try_from_str_radix_impl(out, StrBegin(digits), StrLen(digits), start, radix, true);
    }
        }
    
        return int_try_from_str_radix_impl(out, StrBegin(binary), StrLen(binary), start, 2, true);
    }
        }
    
        return int_try_from_str_radix_impl(out, StrBegin(octal), StrLen(octal), start, 8, true);
    }
        }
    
        return int_try_from_str_radix_impl(out, StrBegin(hex), StrLen(hex), 0, 16, false);
    }
            LOG_FATAL("Invalid arguments");
        }
        return float_try_from_str_impl(out, StrBegin(text), StrLen(text));
    }
        bool result = false;
    
        if (ZstrFindSubstring(StrBegin(&bv_str), pattern) != NULL) {
            result = true;
        }
        bool result = false;
    
        if (ZstrFindSubstringN(StrBegin(&bv_str), StrBegin(pattern), StrLen(pattern)) != NULL) {
            result = true;
        }
                break;
            }
            char *data = StrBegin(&search_path);
            MemCopy(data, path, path_len);
            data[path_len]     = '\\';
        i8 ok = 1;
        StrInitStack(buf, 4096) {
            char *data = StrBegin(&buf);
            MemCopy(data, path, n);
            data[n] = 0;
        for (size i = 0; i < VecLen(&dc); ++i) {
            DirEntry *e        = VecPtrAt(&dc, i);
            Zstr      entry_nm = StrBegin(&e->name);
            if (ZstrCompare(entry_nm, ".") == 0 || ZstrCompare(entry_nm, "..") == 0) {
                continue;
            append_build_id_path(&path, main->build_id, main->build_id_size);
            StrPushBackMany(&path, ".debug");
            if (sys_path_exists(StrBegin(&path)) && ElfOpen(out, &path, alloc)) {
                if (sidecar_matches(main, out, /*by_build_id*/ true)) {
                    StrDeinit(&path);
            StrPushBackR(&path, '/');
            StrPushBackMany(&path, main->debuglink_name);
            if (sys_path_exists(StrBegin(&path)) && ElfOpen(out, &path, alloc)) {
                if (sidecar_matches(main, out, /*by_build_id*/ false)) {
                    StrDeinit(&path);
            StrPushBackMany(&path, "/.debug/");
            StrPushBackMany(&path, main->debuglink_name);
            if (sys_path_exists(StrBegin(&path)) && ElfOpen(out, &path, alloc)) {
                if (sidecar_matches(main, out, /*by_build_id*/ false)) {
                    StrDeinit(&path);
            StrPushBackR(&path, '/');
            StrPushBackMany(&path, main->debuglink_name);
            if (sys_path_exists(StrBegin(&path)) && ElfOpen(out, &path, alloc)) {
                if (sidecar_matches(main, out, /*by_build_id*/ false)) {
                    StrDeinit(&path);
        *out_path = StrInit(StrAllocator(out_path));
        StrPushBackMany(out_path, cv->pdb_path);
        if (sys_path_exists(StrBegin(out_path)))
            return true;
            StrPushBackR(out_path, '/');
        StrPushBackMany(out_path, pdb_base);
        if (sys_path_exists(StrBegin(out_path)))
            return true;
    
        Str pdb_path = StrInit(alloc);
        if (!find_pdb(&entry->pe, StrBegin(&entry->module_path), &pdb_path)) {
            StrDeinit(&pdb_path);
            return false;
        for (size i = 0; i < VecLen(&self->entries); ++i) {
            PdbCacheEntry *e = VecPtrAt(&self->entries, i);
            if (StrBegin(&e->module_path) && ZstrCompare(StrBegin(&e->module_path), module_path) == 0) {
                return e;
            }
            return false;
        }
        return pdb_cache_resolve_zstr(self, StrBegin(module_path), module_base, runtime_ip, out_name, out_offset);
    }
        bool ok = true;
        StrInitStack(chunk, 4096) {
            char *data = StrBegin(&chunk);
            for (;;) {
                i64 n = FileRead(&f, data, 4096);
                StrInitStack(ip_buf, 64) {
                    StrPushBackMany(&ip_buf, (Zstr)StrIterDataAt(&si, ip_start), ip_len);
                    got_v4 = parse_ipv4(StrBegin(&ip_buf), v4);
                    if (!got_v4) {
                        got_v6 = parse_ipv6(StrBegin(&ip_buf), v6);
                    got_v4 = parse_ipv4(StrBegin(&ip_buf), v4);
                    if (!got_v4) {
                        got_v6 = parse_ipv6(StrBegin(&ip_buf), v6);
                    }
                }
                HostsEntry e = {0};
                e.name       = StrInitFromCstr((Zstr)StrIterDataAt(&si, nm_start), nm_len, alloc);
                ascii_lower((u8 *)StrBegin(&e.name), StrLen(&e.name));
                if (got_v4) {
                    MemCopy(e.ip, v4, 4);
                        u8 v4[4]  = {0};
                        u8 v6[16] = {0};
                        if (parse_ipv4(StrBegin(&ip_buf), v4)) {
                            SocketAddr a = sockaddr_v4(v4, 53);
                            VecPushBackR(out, a);
                            SocketAddr a = sockaddr_v4(v4, 53);
                            VecPushBackR(out, a);
                        } else if (parse_ipv6(StrBegin(&ip_buf), v6)) {
                            SocketAddr a = sockaddr_v6(v6, 53);
                            VecPushBackR(out, a);
        Str buf = StrInit(self->allocator);
        StrPushBackMany(&buf, path, len);
        bool ok = dns_add_path(self, StrBegin(&buf), do_hosts, do_resolv);
        StrDeinit(&buf);
        return ok;
        if (!self || !path)
            return false;
        return dns_add_path(self, StrBegin(path), true, true);
    }
        if (!self || !path)
            return false;
        return dns_add_path(self, StrBegin(path), true, false);
    }
        if (!self || !path)
            return false;
        return dns_add_path(self, StrBegin(path), false, true);
    }
            // is a valid Zstr for the matchers / DNS query below.
            normalize_hostname(hostname, &norm);
            Zstr nq = StrBegin(&norm);
    
            // 1. /etc/hosts fast path.
            // 1. /etc/hosts fast path.
            VecForeachPtr(&self->hosts, e) {
                if (StrLen(&e->name) > 0 && ZstrCompare(StrBegin(&e->name), nq) == 0) {
                    SocketAddr a = e->is_ipv6 ? sockaddr_v6(e->ip, port) : sockaddr_v4(e->ip, port);
                    VecPushBackR(out, a);
        StrInitStack(host, 256) {
            StrPushBackMany(&host, spec, colon_at);
            ok = dns_resolve_5_zstr(self, StrBegin(&host), port, kind, out);
        }
        return ok;
            return false;
        }
        return dns_resolve_5_zstr(self, StrBegin(hostname), port, kind, out);
    }
            return false;
        }
        return dns_resolve_4_vec_zstr(self, StrBegin(spec), kind, out);
    }
            return false;
        }
        return dns_resolve_4_one_zstr(self, StrBegin(spec), kind, out);
    }
            if (pdb_cache_ok) {
                StrInitStack(module_path, MAX_PATH) {
                    char *data        = StrBegin(&module_path);
                    u64   module_base = 0;
                    if (win_module_for_ip(frames[i].ip, data, MAX_PATH, &module_base)) {
            bool iter_ok = true;
            StrInitStack(tmp, 4) {
                char *data = StrBegin(&tmp);
                i32   n    = 0;
                if (v == 0) {
        bool ok = true;
        StrInitStack(tmp, 4) {
            char *data = StrBegin(&tmp);
            i32   n    = 0;
            if (v == 0) {
        bool ok = false;
        StrInitStack(host, 256) {
            char *host_data = StrBegin(&host);
            Zstr  port_str  = NULL;
            if (!split_host_port(spec, host_data, 256, &port_str)) {
        // semantics for non-degenerate input. The empty-spec edge case is
        // already handled by the zstr arm (returns false on no colon).
        return socket_addr_parse_zstr(out, StrBegin(spec), kind);
    }
    
        StrInitStack(host, 48) {
            char *host_data = StrBegin(&host);
            u16   port      = 0;
            if (addr->family == SOCKET_FAMILY_INET) {
        for (size i = 0; i < VecLen(&self->entries); ++i) {
            MachoCacheEntry *e = VecPtrAt(&self->entries, i);
            if (StrBegin(&e->module_path) && ZstrCompare(StrBegin(&e->module_path), module_path) == 0) {
                return e;
            }
    
        Str path = StrInit(alloc);
        if (!compose_dsym_path(StrBegin(&e->module_path), &path)) {
            StrDeinit(&path);
            return false;
            return false;
        }
        if (!sys_path_exists(StrBegin(&path)) || !MachoOpen(&e->dsym, &path, alloc)) {
            StrDeinit(&path);
            return false;
            return false;
        }
        return macho_cache_resolve_zstr(self, StrBegin(module_path), slide, runtime_ip, out_name, out_offset);
    }
        }
    
        if (!CreateProcessA(NULL, StrBegin(&cmdline), NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi)) {
            LOG_ERROR("CreateProcessA() failed (GetLastError={})", (i32)GetLastError());
            StrDeinit(&cmdline);
    
    #if PLATFORM_UNIX
        return direct_sys3(MISRA_SYS_write, (long)(proc->_stdin_fd), (long)(u64)(StrBegin(buf)), (long)(StrLen(buf)));
    #else
        DWORD written = 0;
    #else
        DWORD written = 0;
        if (!WriteFile(proc->_hStdinWrite, StrBegin(buf), StrLen(buf), &written, NULL))
            return -1;
        return (int)written;
    
            while (true) {
                ssize_t n = direct_sys3(MISRA_SYS_read, (long)(rfd), (long)(u64)(StrBegin(&tmpbuf)), (long)(1023));
                if (n > 0) {
                    StrResize(&tmpbuf, (size)n);
    
                DWORD bytes_read = 0;
                if (!ReadFile(rhandle, StrBegin(&tmpbuf), 1023, &bytes_read, NULL)) {
                    LOG_ERROR("ReadFile failed (GetLastError={})", (i32)GetLastError());
                    total_read = -1;
        bool got = false;
        StrInitStack(buffer, MAX_PATH) {
            DWORD len = GetModuleFileNameA(NULL, StrBegin(&buffer), MAX_PATH);
            if (len == 0 || len >= MAX_PATH) {
                LOG_ERROR("Failed to get executable path or buffer too small");
        bool got = false;
        StrInitStack(buffer, 4096) {
            char   *data = StrBegin(&buffer);
            ssize_t len  = proc_readlink("/proc/self/exe", data, 4095);
            if (len >= 0) {
        if (!self || !name)
            return NULL;
        return pe_find_section_zstr(self, StrBegin(name));
    }
                        .low_pc  = pf->low_pc,
                        .high_pc = pf->high_pc,
                        .name    = StrBegin(&out->string_pool) + pf->name_offset_in_pool,
                };
                if (!VecPushBackR(&out->entries, f)) {
        // Str values are NUL-terminated by construction; encode_qname scans
        // to '\0', so forward the Str's data view directly.
        return dns_build_query_zstr(out, id, StrBegin(name), type);
    }
        }
    
        parsed = ZstrToI64(StrBegin(value), &endptr);
    
        if (!endptr || endptr == StrBegin(value) || *endptr != '\0') {
        parsed = ZstrToI64(StrBegin(value), &endptr);
    
        if (!endptr || endptr == StrBegin(value) || *endptr != '\0') {
            return false;
        }
        }
    
        parsed = ZstrToF64(StrBegin(value), &endptr);
    
        if (!endptr || endptr == StrBegin(value) || *endptr != '\0') {
        parsed = ZstrToF64(StrBegin(value), &endptr);
    
        if (!endptr || endptr == StrBegin(value) || *endptr != '\0') {
            return false;
        }
        }
    
        return StrInitFromCstr(StrBegin(value), StrLen(value), MapAllocator(cfg));
    }
        }
    
        return StrInitFromCstr(StrBegin(value), StrLen(value), MapAllocator(cfg));
    }
                       .rva  = pp->rva,
                       .size = 0,
                       .name = StrBegin(&self->name_pool) + pp->name_offset_in_pool,
            };
            if (i + 1 < VecLen(&pending)) {
        }
        VecForeachPtr(headers, header) {
            if (0 == ZstrCompare(StrBegin(&header->key), key)) {
                return header;
            }
        // Str values are NUL-terminated by construction; comparison scans
        // to '\0', so forward the .data view.
        return http_headers_find_zstr(headers, StrBegin(key));
    }
    
    static HttpRequestMethod http_request_method_from_str(const Str *mstr) {
        if (!mstr || !StrBegin(mstr)) {
            return HTTP_REQUEST_METHOD_UNKNOWN;
        }
            return HTTP_REQUEST_METHOD_UNKNOWN;
        }
        if (0 == ZstrCompareN(StrBegin(mstr), "GET", 3) && StrLen(mstr) == 3)
            return HTTP_REQUEST_METHOD_GET;
        if (0 == ZstrCompareN(StrBegin(mstr), "POST", 4) && StrLen(mstr) == 4)
        if (0 == ZstrCompareN(StrBegin(mstr), "GET", 3) && StrLen(mstr) == 3)
            return HTTP_REQUEST_METHOD_GET;
        if (0 == ZstrCompareN(StrBegin(mstr), "POST", 4) && StrLen(mstr) == 4)
            return HTTP_REQUEST_METHOD_POST;
        if (0 == ZstrCompareN(StrBegin(mstr), "DELETE", 6) && StrLen(mstr) == 6)
        if (0 == ZstrCompareN(StrBegin(mstr), "POST", 4) && StrLen(mstr) == 4)
            return HTTP_REQUEST_METHOD_POST;
        if (0 == ZstrCompareN(StrBegin(mstr), "DELETE", 6) && StrLen(mstr) == 6)
            return HTTP_REQUEST_METHOD_DELETE;
        if (0 == ZstrCompareN(StrBegin(mstr), "PUT", 3) && StrLen(mstr) == 3)
        if (0 == ZstrCompareN(StrBegin(mstr), "DELETE", 6) && StrLen(mstr) == 6)
            return HTTP_REQUEST_METHOD_DELETE;
        if (0 == ZstrCompareN(StrBegin(mstr), "PUT", 3) && StrLen(mstr) == 3)
            return HTTP_REQUEST_METHOD_PUT;
        if (0 == ZstrCompareN(StrBegin(mstr), "PATCH", 5) && StrLen(mstr) == 5)
        if (0 == ZstrCompareN(StrBegin(mstr), "PUT", 3) && StrLen(mstr) == 3)
            return HTTP_REQUEST_METHOD_PUT;
        if (0 == ZstrCompareN(StrBegin(mstr), "PATCH", 5) && StrLen(mstr) == 5)
            return HTTP_REQUEST_METHOD_PATCH;
        if (0 == ZstrCompareN(StrBegin(mstr), "HEAD", 4) && StrLen(mstr) == 4)
        if (0 == ZstrCompareN(StrBegin(mstr), "PATCH", 5) && StrLen(mstr) == 5)
            return HTTP_REQUEST_METHOD_PATCH;
        if (0 == ZstrCompareN(StrBegin(mstr), "HEAD", 4) && StrLen(mstr) == 4)
            return HTTP_REQUEST_METHOD_HEAD;
        if (0 == ZstrCompareN(StrBegin(mstr), "OPTIONS", 7) && StrLen(mstr) == 7)
        if (0 == ZstrCompareN(StrBegin(mstr), "HEAD", 4) && StrLen(mstr) == 4)
            return HTTP_REQUEST_METHOD_HEAD;
        if (0 == ZstrCompareN(StrBegin(mstr), "OPTIONS", 7) && StrLen(mstr) == 7)
            return HTTP_REQUEST_METHOD_OPTIONS;
        if (0 == ZstrCompareN(StrBegin(mstr), "CONNECT", 7) && StrLen(mstr) == 7)
        if (0 == ZstrCompareN(StrBegin(mstr), "OPTIONS", 7) && StrLen(mstr) == 7)
            return HTTP_REQUEST_METHOD_OPTIONS;
        if (0 == ZstrCompareN(StrBegin(mstr), "CONNECT", 7) && StrLen(mstr) == 7)
            return HTTP_REQUEST_METHOD_CONNECT;
        if (0 == ZstrCompareN(StrBegin(mstr), "TRACE", 5) && StrLen(mstr) == 5)
        if (0 == ZstrCompareN(StrBegin(mstr), "CONNECT", 7) && StrLen(mstr) == 7)
            return HTTP_REQUEST_METHOD_CONNECT;
        if (0 == ZstrCompareN(StrBegin(mstr), "TRACE", 5) && StrLen(mstr) == 5)
            return HTTP_REQUEST_METHOD_TRACE;
        return HTTP_REQUEST_METHOD_UNKNOWN;
        }
    
        if (0 != ZstrCompareN(StrBegin(&version), "HTTP/1.1", 8)) {
            LOG_ERROR("invalid/unsupported HTTP version");
            StrDeinit(&method);
        // parser scans format-by-format with NUL-aware readers, so the
        // .data view is sufficient.
        return http_request_parse_zstr(req, StrBegin(in));
    }
            LOG_FATAL("invalid arguments");
        }
        return http_respond_with_file_zstr(response, status, content_type, (Zstr)StrBegin(filepath));
    }
    #endif
    
        if (StrLen(&response->body)) {
            if (!StrPushBackMany(&out, StrBegin(&response->body), StrLen(&response->body))) {
                LOG_ERROR("HttpResponseSerialize: failed to append body");
                StrDeinit(&out);
        Zstr end = NULL;
        if (is_flt) {
            num->f = ZstrToF64(StrBegin(&ns), &end);
        } else {
            num->i = ZstrToI64(StrBegin(&ns), &end);
            num->f = ZstrToF64(StrBegin(&ns), &end);
        } else {
            num->i = ZstrToI64(StrBegin(&ns), &end);
        }
        if (end == StrBegin(&ns)) {
            num->i = ZstrToI64(StrBegin(&ns), &end);
        }
        if (end == StrBegin(&ns)) {
            LOG_ERROR("Failed to convert string to number.");
            StrDeinit(&ns);
        if (!self || !name)
            return NULL;
        return elf_find_section_zstr(self, StrBegin(name));
    }
                u64 fo                           = VecAt(&pending_file_offsets, i);
                u64 dofs                         = VecAt(&pending_dir_offsets, i);
                VecPtrAt(&out->entries, i)->file = fo ? (Zstr)(StrBegin(&out->string_pool) + fo) : NULL;
                VecPtrAt(&out->entries, i)->dir  = dofs ? (Zstr)(StrBegin(&out->string_pool) + dofs) : NULL;
            }
                u64 dofs                         = VecAt(&pending_dir_offsets, i);
                VecPtrAt(&out->entries, i)->file = fo ? (Zstr)(StrBegin(&out->string_pool) + fo) : NULL;
                VecPtrAt(&out->entries, i)->dir  = dofs ? (Zstr)(StrBegin(&out->string_pool) + dofs) : NULL;
            }
        }
                // bracket form on v6 to round-trip through SocketAddrParse.
                size n = StrLen(&s);
                Zstr p = StrBegin(&s);
                if (n >= 2 && p[n - 1] == '0' && p[n - 2] == ':') {
                    StrMustResize(&s, n - 2);
    
            HttpRequest req = HttpRequestInit(scope);
            Zstr        end = HttpRequestParse(&req, (Zstr)StrBegin(&raw));
            if (end == StrBegin(&raw)) {
                LOG_INFO("[{}] (unparseable request, {} bytes)", client_addr, (u64)prefix_len);
            HttpRequest req = HttpRequestInit(scope);
            Zstr        end = HttpRequestParse(&req, (Zstr)StrBegin(&raw));
            if (end == StrBegin(&raw)) {
                LOG_INFO("[{}] (unparseable request, {} bytes)", client_addr, (u64)prefix_len);
            } else {
        if ((size)first_n < sizeof(first)) {
            first[first_n] = 0;
            log_request_summary(StrBegin(&peer_str), first, (size)first_n);
        } else {
            LOG_INFO("[{}] (request larger than {} bytes, not logging line)", peer_str, (u64)sizeof(first));
    
        bool result = (got == (i64)ZstrLen("hello from file")) && (StrLen(&body) == (size)ZstrLen("hello from file")) &&
                      ZstrCompare(StrBegin(&body), "hello from file") == 0;
    
        StrDeinit(&body);
        Zstr expected = "this is longer than the initial buffer";
        bool result   = (got == (i64)ZstrLen(expected)) && (StrLen(&body) == (size)ZstrLen(expected)) &&
                      ZstrCompare(StrBegin(&body), expected) == 0 && StrCapacity(&body) >= StrLen(&body) + 1;
    
        StrDeinit(&body);
        FileClose(&r);
    
        ok = ok && (got == 3) && (StrLen(&body) == 3) && ZstrCompare(StrBegin(&body), "new") == 0;
    
        StrDeinit(&body);
        FileClose(&r);
    
        ok = ok && (got == 8) && ZstrCompare(StrBegin(&body), "headtail") == 0;
    
        StrDeinit(&body);
        Str body = StrInit(alloc_base);
        i64 got  = FileReadAndClose(&path, &body);
        ok       = ok && (got == (i64)n) && (StrLen(&body) == (size)n) && ZstrCompare(StrBegin(&body), payload) == 0;
    
        StrDeinit(&body);
        i64  got  = FileRead(&r, &body);
        FileClose(&r);
        ok = ok && (got == 10) && ZstrCompare(StrBegin(&body), "AAA3456789") == 0;
    
        StrDeinit(&body);
        Str body = StrInit(alloc_base);
        i64 got  = FileReadAndClose(&path, &body);
        ok       = ok && (got == 10) && ZstrCompare(StrBegin(&body), "helloworld") == 0;
    
        StrDeinit(&body);
        FileClose(&f);
    
        ok = ok && (got == 6) && (StrLen(&body) == 6) && ZstrCompare(StrBegin(&body), "ABCDEF") == 0;
    
        StrDeinit(&body);
    
        ok = ok && (got == (i64)ZstrLen(payload)) && (StrLen(&body) == (size)ZstrLen(payload)) &&
             ZstrCompare(StrBegin(&body), payload) == 0;
    
        StrDeinit(&body);
        Str body = StrInit(alloc_base);
        i64 got  = FileReadAndClose(&path, &body);
        ok       = ok && (got == (i64)n) && (StrLen(&body) == (size)n) && ZstrCompare(StrBegin(&body), payload) == 0;
    
        StrDeinit(&body);
        Str body = StrInit(alloc_base);
        i64 got  = FileReadAndClose(&path, &body);
        ok       = ok && (got == 5) && ZstrCompare(StrBegin(&body), "12345") == 0;
    
        StrDeinit(&body);
        Str body = StrInit(alloc_base);
        i64 got  = FileReadAndClose(&path, &body);
        ok       = ok && (got == (i64)StrLen(&in)) && ZstrCompare(StrBegin(&body), "string-content") == 0;
    
        StrDeinit(&body);
        ok      = ok && (StrLen(&p1) == 16) && (StrLen(&p2) == 16);
        // Distinct names (overwhelmingly likely; the loop draws fresh entropy).
        ok = ok && (ZstrCompare(StrBegin(&p1), StrBegin(&p2)) != 0);
    
        // They are independent files: writing to one does not affect the other.
        Str b1 = StrInit(alloc_base);
        Str b2 = StrInit(alloc_base);
        ok     = ok && (FileReadAndClose(&p1, &b1) == 3) && ZstrCompare(StrBegin(&b1), "one") == 0;
        ok     = ok && (FileReadAndClose(&p2, &b2) == 6) && ZstrCompare(StrBegin(&b2), "twotwo") == 0;
        Str b2 = StrInit(alloc_base);
        ok     = ok && (FileReadAndClose(&p1, &b1) == 3) && ZstrCompare(StrBegin(&b1), "one") == 0;
        ok     = ok && (FileReadAndClose(&p2, &b2) == 6) && ZstrCompare(StrBegin(&b2), "twotwo") == 0;
    
        StrDeinit(&b1);
    
        bool ok = StrLen(&out) > 0;
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "24 bytes") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "40 bytes") != NULL);
        bool ok = StrLen(&out) > 0;
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "24 bytes") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "40 bytes") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "24 bytes") != NULL);
        ok      = ok && (ZstrFindSubstring(StrBegin(&out), "40 bytes") != NULL);
    
        StrDeinit(&out);
        DebugAllocatorReportLeaks(&dbg, &out);
    
        bool ok = (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // FormatStackTrace renders frame lines beginning with "#0".
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#0") != NULL);
        bool ok = (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // FormatStackTrace renders frame lines beginning with "#0".
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#0") != NULL);
    
        StrDeinit(&out);
        DebugAllocatorReportLeaks(&dbg, &out);
    
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // Real emits "#0" and "#1"; the `--i` mutant emits only "#0".
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#0 ") != NULL);
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // Real emits "#0" and "#1"; the `--i` mutant emits only "#0".
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#0 ") != NULL);
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#1 ") != NULL);
        // Real emits "#0" and "#1"; the `--i` mutant emits only "#0".
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#0 ") != NULL);
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "#1 ") != NULL);
    
        StrDeinit(&out);
        StrAppendFmt(&ns, "#{} ", n);
    
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // The valid top frame "#(N-1) " is present; the spurious "#N " is not.
        ok = ok && (ZstrFindSubstring(StrBegin(&out), StrBegin(&ns)) == NULL);
        ok = ok && (ZstrFindSubstring(StrBegin(&out), "leak:") != NULL);
        // The valid top frame "#(N-1) " is present; the spurious "#N " is not.
        ok = ok && (ZstrFindSubstring(StrBegin(&out), StrBegin(&ns)) == NULL);
    
        StrDeinit(&ns);
        ArgRun rc     = ArgParseRun(&p, 3, argv);
    
        bool ok = (rc == ARG_RUN_OK) && StrLen(&name) == 5 && StrBegin(&name)[0] == 'a' && StrBegin(&name)[4] == 'e';
        ArgParseDeinit(&p);
        StrDeinit(&name);
        Str              out = StrInit(&a);
        capture_help(p, &out);
        bool ok = (StrLen(&out) == ZstrLen(expected)) && (ZstrCompare(StrBegin(&out), expected) == 0);
        if (!ok) {
            WriteFmt("[a1] help mismatch:\n");
            WriteFmt("[a1] help mismatch:\n");
            WriteFmt("---- expected ({} bytes) ----\n{}\n", ZstrLen(expected), expected);
            WriteFmt("---- actual   ({} bytes) ----\n{}\n", StrLen(&out), StrBegin(&out));
        }
        StrDeinit(&out);
    
        // opt50 is inside the 64-row window (rendered); opt64 is past it.
        bool ok = ZstrFindSubstring(StrBegin(&out), "--opt50") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt00") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt64") == NULL;
        // opt50 is inside the 64-row window (rendered); opt64 is past it.
        bool ok = ZstrFindSubstring(StrBegin(&out), "--opt50") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt00") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt64") == NULL;
        if (!ok) {
        bool ok = ZstrFindSubstring(StrBegin(&out), "--opt50") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt00") != NULL &&
                  ZstrFindSubstring(StrBegin(&out), "--opt64") == NULL;
        if (!ok) {
            WriteFmt("[a1] render cap: window wrong\n{}\n", StrBegin(&out));
                  ZstrFindSubstring(StrBegin(&out), "--opt64") == NULL;
        if (!ok) {
            WriteFmt("[a1] render cap: window wrong\n{}\n", StrBegin(&out));
        }
        StrDeinit(&out);
    static bool str_contains(Str *hay, Zstr needle) {
        u64  hn  = StrLen(hay);
        Zstr beg = StrBegin(hay);
        u64  nn  = ZstrLen(needle);
        if (nn == 0)
        char  *argv[] = {(char *)"prog", (char *)"--name", (char *)"bob"};
        ArgRun rc     = ArgParseRun(&p, 3, argv);
        bool ok = (rc == ARG_RUN_OK) && (StrLen(&name) == 3) && (StrBegin(&name)[0] == 'b') && (StrBegin(&name)[2] == 'b');
        ArgParseDeinit(&p);
        StrDeinit(&name);
    static bool str_has(Str *hay, Zstr needle) {
        u64  hn  = StrLen(hay);
        Zstr beg = StrBegin(hay);
        u64  nn  = ZstrLen(needle);
        if (nn == 0)
        DateTime         d     = DateTimeFromUnixNs(T_2021 * NS_PER_SEC, 0);
        StrAppendFmt(&s, "{}", d);
        bool ok = ZstrCompare(StrBegin(&s), "2021-01-01T00:00:00Z") == 0;
        StrDeinit(&s);
        DefaultAllocatorDeinit(&alloc);
        DateTime         d     = DateTimeFromUnixNs(T_2021 * NS_PER_SEC, IST);
        StrAppendFmt(&s, "{}", d);
        bool ok = ZstrCompare(StrBegin(&s), "2021-01-01T05:30:00+05:30") == 0;
        StrDeinit(&s);
        DefaultAllocatorDeinit(&alloc);
        DateTime         d     = DateTimeFromUnixNs(T_2021 * NS_PER_SEC + 123456789ull, 0);
        StrAppendFmt(&s, "{}", d);
        bool ok = ZstrCompare(StrBegin(&s), "2021-01-01T00:00:00.123456789Z") == 0;
        StrDeinit(&s);
        DefaultAllocatorDeinit(&alloc);
    
        DateTime b = {0};
        Zstr     p = StrBegin(&s);
        StrReadFmt(p, "{}", b);
        stored_name = GraphNodeDataPtr(&graph, node);
    
        bool result = GraphNodeIdIndex(node_id) == 0 && StrBegin(&name) != NULL && GraphNodeCount(&graph) == 1 &&
                      ZstrCompare(StrBegin(stored_name), "alpha") == 0 && StrBegin(stored_name) != StrBegin(&name);
    
        bool result = GraphNodeIdIndex(node_id) == 0 && StrBegin(&name) != NULL && GraphNodeCount(&graph) == 1 &&
                      ZstrCompare(StrBegin(stored_name), "alpha") == 0 && StrBegin(stored_name) != StrBegin(&name);
    
        StrDeinit(&name);
        stored_name = GraphNodeDataPtr(&graph, node);
    
        bool result = GraphNodeIdIndex(node_id) == 0 && GraphNodeCount(&graph) == 1 && StrBegin(stored_name) != NULL &&
                      ZstrCompare(StrBegin(stored_name), "alpha") == 0;
    
        bool result = GraphNodeIdIndex(node_id) == 0 && GraphNodeCount(&graph) == 1 && StrBegin(stored_name) != NULL &&
                      ZstrCompare(StrBegin(stored_name), "alpha") == 0;
    
        GraphDeinit(&graph);
    
    static GraphNodeId city_add_intersection(CityGraph *graph, CityIndex *index, const Str *name, DefaultAllocator *alloc) {
        GraphNodeId id = GraphAddNodeR(graph, StrInitFromCstr(StrBegin(name), StrLen(name), alloc));
    
        Str key_copy = StrInitFromCstr(StrBegin(name), StrLen(name), alloc);
        GraphNodeId id = GraphAddNodeR(graph, StrInitFromCstr(StrBegin(name), StrLen(name), alloc));
    
        Str key_copy = StrInitFromCstr(StrBegin(name), StrLen(name), alloc);
        MapInsertR(index, key_copy, id);
        return id;
    
        bool result = FloatEQ(&clone, &expected);
        result      = result && (ZstrCompare(StrBegin(&text), "-12.5") == 0);
        result      = result && !FloatEQ(&clone, &original);
    
        Str  text  = IntToStr(&result);
        bool right = ok && (ZstrCompare(StrBegin(&text), "5") == 0);
    
        StrDeinit(&text);
    
        Str  text  = IntToStr(&result);
        bool right = ok && (ZstrCompare(StrBegin(&text), "120") == 0);
    
        StrDeinit(&text);
        text = FloatToStr(&f);
    
        bool result = ok && (ZstrCompare(StrBegin(&text), "100") == 0);
    
        StrDeinit(&text);
    
        bool result = (FloatExponent(&value) == 0);
        result      = result && (ZstrCompare(StrBegin(&text), "1152921504606846976") == 0);
    
        StrDeinit(&text);
        FloatAdd(&r, &a, &b);
        t       = FloatToStr(&r);
        bool ok = ZstrCompare(StrBegin(&t), "100.1") == 0;
    
        StrDeinit(&t);
        FloatAdd(&r, &a, &z);
        t       = FloatToStr(&r);
        bool ok = ZstrCompare(StrBegin(&t), "12.5") == 0;
    
        StrDeinit(&t);
        text = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "-12.5") == 0;
    
        StrDeinit(&text);
        FloatAbs(&value);
        text   = FloatToStr(&value);
        result = result && (ZstrCompare(StrBegin(&text), "12.5") == 0);
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "1.23") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), FLOAT_TEST_VERY_LARGE_THREES) == 0;
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, &b);
        text        = FloatToStr(&result_value);
        bool result = ZstrCompare(StrBegin(&text), "2") == 0;
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, &whole);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3.25") == 0);
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, 2u);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3.25") == 0);
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, -1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "0.25") == 0);
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, 0.75f);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "2") == 0);
    
        StrDeinit(&text);
        FloatAdd(&result_value, &a, 0.75);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "2") == 0);
    
        FloatDeinit(&a);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "-0.5") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), FLOAT_TEST_VERY_LARGE_TWOS) == 0;
    
        StrDeinit(&text);
        FloatSub(&result_value, &a, &b);
        text        = FloatToStr(&result_value);
        bool result = ZstrCompare(StrBegin(&text), "5") == 0;
    
        StrDeinit(&text);
        FloatSub(&result_value, &a, &whole);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3.5") == 0);
    
        StrDeinit(&text);
        FloatSub(&result_value, &a, 2u);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3.5") == 0);
    
        StrDeinit(&text);
        FloatSub(&result_value, &a, -2);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "7.5") == 0);
    
        StrDeinit(&text);
        FloatSub(&result_value, &a, 0.5f);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "5") == 0);
    
        FloatDeinit(&a);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "-2.5") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), FLOAT_TEST_VERY_LARGE_TWOS) == 0;
    
        StrDeinit(&text);
        FloatMul(&result_value, &a, &b);
        text        = FloatToStr(&result_value);
        bool result = ZstrCompare(StrBegin(&text), "3") == 0;
    
        StrDeinit(&text);
        FloatMul(&result_value, &a, &whole);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3") == 0);
    
        StrDeinit(&text);
        FloatMul(&result_value, &a, 2u);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "3") == 0);
    
        StrDeinit(&text);
        FloatMul(&result_value, &a, -2);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "-3") == 0);
    
        StrDeinit(&text);
        FloatMul(&result_value, &a, 0.5f);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "0.75") == 0);
    
        FloatDeinit(&a);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "0.125") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), FLOAT_TEST_VERY_LARGE_ONES) == 0;
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, &b, 1);
        text        = FloatToStr(&result_value);
        bool result = ZstrCompare(StrBegin(&text), "3") == 0;
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, &whole, 1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "2.5") == 0);
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, 3u, 1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "2.5") == 0);
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, -3, 1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "-2.5") == 0);
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, 0.5f, 1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "15") == 0);
    
        StrDeinit(&text);
        FloatDiv(&result_value, &a, 0.5, 1);
        text   = FloatToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "15") == 0);
    
        FloatDeinit(&a);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "3") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "-3") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "0.75") == 0;
    
        StrDeinit(&text);
        text = FloatToStr(&f);
    
        bool result = ok && (ZstrCompare(StrBegin(&text), "5") == 0);
    
        StrDeinit(&text);
        text = FloatToStr(&f);
    
        bool result = ok && (ZstrCompare(StrBegin(&text), "19") == 0);
    
        StrDeinit(&text);
        bool ok     = FloatDiv(&quotient, &a, &b, 8);
        text        = FloatToStr(&quotient);
        bool result = ok && (ZstrCompare(StrBegin(&text), "2") == 0);
    
        StrDeinit(&text);
        bool ok = FloatDiv(&r, &a, 3u, 1);
        text    = FloatToStr(&r);
        ok      = ok && (ZstrCompare(StrBegin(&text), "2.5") == 0);
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "42") == 0;
        result      = result && !FloatIsNegative(&value);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "-42") == 0;
        result      = result && FloatIsNegative(&value);
        Str   text    = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "12345678901234567890") == 0;
    
        IntDeinit(&integer);
        bool result = FloatToInt(&result_value, &value);
        text        = IntToStr(&result_value);
        result      = result && (ZstrCompare(StrBegin(&text), "12345") == 0);
    
        FloatDeinit(&value);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "-123.45") == 0;
    
        StrDeinit(&text);
        ok = float_try_to_str(&text, &value, ALLOCATOR_OF(&alloc));
    
        bool result = ok && (ZstrCompare(StrBegin(&text), "-123.45") == 0) &&
                      (StrAllocator(&text)->effort == alloc.base.effort) &&
                      (StrAllocator(&text)->retry_limit == alloc.base.retry_limit);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), FLOAT_TEST_VERY_LARGE_ONES) == 0;
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "1230") == 0;
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), "100") == 0;
        result      = result && (FloatCompare(&value, &whole) == 0);
    
        result = result && FloatIsNegative(&value);
        result = result && (ZstrCompare(StrBegin(&text), "-2000") == 0);
        result = result && (FloatExponent(&value) == 3);
        Float value = FloatFrom((u64)100, &alloc.base);
        Str   text  = FloatToStr(&value);
        bool  ok    = ZstrCompare(StrBegin(&text), "100") == 0;
    
        StrDeinit(&text);
    
        Str printed = FloatToStr(&value);
        ok          = ok && (ZstrCompare(StrBegin(&printed), "3.14") == 0);
    
        StrDeinit(&printed);
        Str   text  = FloatToStr(&value);
    
        bool result = (ZstrCompare(StrBegin(&text), "3.14") == 0) && (StrLen(&text) == 4);
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = (ZstrCompare(StrBegin(&text), "0.001") == 0) && (StrLen(&text) == 5);
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = (ZstrCompare(StrBegin(&text), "100") == 0) && (StrLen(&text) == 3);
    
        StrDeinit(&text);
    
        Str text = FloatToStr(&value);
        ok       = ok && (ZstrCompare(StrBegin(&text), "1") == 0);
    
        StrDeinit(&text);
        Str   text  = FloatToStr(&value);
    
        bool result = (ZstrCompare(StrBegin(&text), "4503599627370496") == 0) && (StrLen(&text) == 16);
    
        StrDeinit(&text);
        StrClear(&s);
    
        bool result = (StrLen(&s) == 0) && (ZstrCompare(StrBegin(&s), "") == 0);
    
        StrDeinit(&s);
        StrClear(&s);
    
        bool result = (StrLen(&s) == 0) && (ZstrCompare(StrBegin(&s), "") == 0);
    
        StrDeinit(&s);
        // Check result
        bool result = ok && (StrLen(&str) == 4);
        result      = result && (StrBegin(&str)[0] == '1');
        result      = result && (StrBegin(&str)[1] == '0');
        result      = result && (StrBegin(&str)[2] == '1');
        bool result = ok && (StrLen(&str) == 4);
        result      = result && (StrBegin(&str)[0] == '1');
        result      = result && (StrBegin(&str)[1] == '0');
        result      = result && (StrBegin(&str)[2] == '1');
        result      = result && (StrBegin(&str)[3] == '1');
        result      = result && (StrBegin(&str)[0] == '1');
        result      = result && (StrBegin(&str)[1] == '0');
        result      = result && (StrBegin(&str)[2] == '1');
        result      = result && (StrBegin(&str)[3] == '1');
        result      = result && (StrBegin(&str)[1] == '0');
        result      = result && (StrBegin(&str)[2] == '1');
        result      = result && (StrBegin(&str)[3] == '1');
    
        // Clean up
        result = result && ok && (StrAllocator(&str)->effort == alloc.base.effort) &&
                 (StrAllocator(&str)->retry_limit == alloc.base.retry_limit) &&
                 (ZstrCompare(StrBegin(&str), "101001") == 0);
    
        StrDeinit(&str);
    
            // Should get exact same string back
            result = result && (ZstrCompare(StrBegin(&str), patterns[i]) == 0);
    
            StrDeinit(&str);
            // Test string conversion consistency
            Str str = BitVecToStr(&bv);
            result  = result && (ZstrCompare(StrBegin(&str), test_cases[i].pattern) == 0);
            StrDeinit(&str);
        // str2 and str3 are the same integer/byte packing; str1 is the string
        // form. Assert each exactly.
        result = result && (ZstrCompare(StrBegin(&str1), "11010110") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str3), "01101011") == 0);
        // form. Assert each exactly.
        result = result && (ZstrCompare(StrBegin(&str1), "11010110") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str3), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), StrBegin(&str3)) == 0);
        result = result && (ZstrCompare(StrBegin(&str1), "11010110") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str3), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), StrBegin(&str3)) == 0);
        result = result && (ZstrCompare(StrBegin(&str2), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str3), "01101011") == 0);
        result = result && (ZstrCompare(StrBegin(&str2), StrBegin(&str3)) == 0);
    
        StrDeinit(&str1);
        for (u64 i = 0; i < StrLen(&large_str); i++) {
            bool expected = (i % 3) == 0;
            bool actual   = (StrBegin(&large_str)[i] == '1');
            if (expected != actual) {
                pattern_correct = false;
    
        bool result = IntToU64(&result_value) == 256;
        result      = result && (ZstrCompare(StrBegin(&text), "100000000") == 0);
    
        StrDeinit(&text);
        IntAdd(&result_value, &huge, 10);
        text   = IntToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "123456789012345678901234567900") == 0);
    
        IntDeinit(&base);
        result = result && IntSub(&result_value, &huge, 90);
        text   = IntToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "12345678901234567800") == 0);
    
        result = result && !IntSub(&preserved, &base, 50);
        text = IntToStr(&result_value);
    
        bool result = ZstrCompare(StrBegin(&text), "308641972530864197250") == 0;
    
        IntDeinit(&value);
        IntPow(&result_value, &base, 20u);
        text        = IntToStr(&result_value);
        bool result = ZstrCompare(StrBegin(&text), "79792266297612001") == 0;
    
        StrDeinit(&text);
        IntPow(&result_value, &base, &exponent);
        text   = IntToStr(&result_value);
        result = result && (ZstrCompare(StrBegin(&text), "79792266297612001") == 0);
    
        IntDeinit(&base);
        qtext = IntToStr(&quotient);
    
        bool result = ZstrCompare(StrBegin(&qtext), "127275040218913071") == 0;
        result      = result && (IntToU64(&remainder) == 3);
        bool result = IntDivExact(&result_value, &dividend, 90u);
        text        = IntToStr(&result_value);
        result      = result && (ZstrCompare(StrBegin(&text), "137174210013717421") == 0);
    
        IntDeinit(&dividend);
        text = IntToStr(&quotient);
    
        bool result = ZstrCompare(StrBegin(&text), "127275040218913071") == 0;
        result      = result && (IntToU64(&remainder) == 3);
        text    = IntToStr(&next);
    
        bool result = ok && ZstrCompare(StrBegin(&text), "1000000007") == 0;
    
        IntDeinit(&value);
    
        bool result = (IntToU64(&sum) == 128u);
        result      = result && (ZstrCompare(StrBegin(&bits), "10000000") == 0);
    
        StrDeinit(&bits);
    
        bool result = ok;
        result      = result && (ZstrCompare(StrBegin(&qtext), "127275040218913071") == 0);
        result      = result && (IntToU64(&remainder) == 3u);
    
        bool result = ok;
        result      = result && (ZstrCompare(StrBegin(&qtext), "949667607787274453") == 0);
        result      = result && (IntToU64(&remainder) == 1u);
    
        bool result = ok;
        result      = result && (ZstrCompare(StrBegin(&qtext), "12499999874") == 0);
        result      = result && (ZstrCompare(StrBegin(&rtext), "833333448067901235") == 0);
        bool result = ok;
        result      = result && (ZstrCompare(StrBegin(&qtext), "12499999874") == 0);
        result      = result && (ZstrCompare(StrBegin(&rtext), "833333448067901235") == 0);
    
        StrDeinit(&qtext);
        bool result = IntBitLength(&value) == 4;
        result      = result && (IntToU64(&value) == 13);
        result      = result && (ZstrCompare(StrBegin(&text), "1101") == 0);
    
        StrDeinit(&text);
        bool result = written == 4;
        result      = result && (MemCompare(out, bytes, sizeof(bytes)) == 0);
        result      = result && (ZstrCompare(StrBegin(&text), "cdef1234") == 0);
    
        StrDeinit(&text);
        bool result = written == 4;
        result      = result && (MemCompare(out, bytes, sizeof(bytes)) == 0);
        result      = result && (ZstrCompare(StrBegin(&text), "12345678") == 0);
    
        StrDeinit(&text);
    
        bool result = IntToU64(&value) == 11;
        result      = result && (ZstrCompare(StrBegin(&text), "1011") == 0);
    
        StrDeinit(&text);
        Str  text   = IntToStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), digits) == 0;
    
        StrDeinit(&text);
    
        bool result = IntToU64(&value) == 1295;
        result      = result && (ZstrCompare(StrBegin(&text), "zz") == 0);
    
        StrDeinit(&text);
        Str text  = IntToStrRadix(&value, 16, true);
    
        bool result = ZstrCompare(StrBegin(&text), "BEEF") == 0;
    
        StrDeinit(&text);
        ok = int_try_to_str_radix(&text, &value, 16, true, ALLOCATOR_OF(&alloc));
    
        bool result = ok && (ZstrCompare(StrBegin(&text), "BEEF") == 0) &&
                      (StrAllocator(&text)->effort == alloc.base.effort) &&
                      (StrAllocator(&text)->retry_limit == alloc.base.retry_limit);
        result      = result && (IntToU64(&zero, &error) == 0);
        result      = result && !error;
        result      = result && (ZstrCompare(StrBegin(&text), "0") == 0);
    
        StrDeinit(&text);
    
        bool result = IntToU64(&value) == 493;
        result      = result && (ZstrCompare(StrBegin(&text), "755") == 0);
    
        StrDeinit(&text);
        Str  text  = IntToHexStr(&value);
    
        bool result = ZstrCompare(StrBegin(&text), hex) == 0;
    
        StrDeinit(&text);
        Str dec_big   = IntToStrRadix(&big, 10, false, &alloc.base);
    
        bool result = (ZstrCompare(StrBegin(&dec_small), "7") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid), "ff") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid_u), "FF") == 0);
    
        bool result = (ZstrCompare(StrBegin(&dec_small), "7") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid), "ff") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid_u), "FF") == 0);
        result      = result && (ZstrCompare(StrBegin(&dec_big), "123456789012345678901234567890") == 0);
        bool result = (ZstrCompare(StrBegin(&dec_small), "7") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid), "ff") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid_u), "FF") == 0);
        result      = result && (ZstrCompare(StrBegin(&dec_big), "123456789012345678901234567890") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid), "ff") == 0);
        result      = result && (ZstrCompare(StrBegin(&hex_mid_u), "FF") == 0);
        result      = result && (ZstrCompare(StrBegin(&dec_big), "123456789012345678901234567890") == 0);
    
        StrDeinit(&dec_small);
        Str back_hex = IntToStrRadix(&parsed_hex, 16, false, &alloc.base);
    
        bool result = (ZstrCompare(StrBegin(&back_dec), "987654321987654321") == 0);
        result      = result && (ZstrCompare(StrBegin(&back_hex), "deadbeef") == 0);
    
        bool result = (ZstrCompare(StrBegin(&back_dec), "987654321987654321") == 0);
        result      = result && (ZstrCompare(StrBegin(&back_hex), "deadbeef") == 0);
    
        StrDeinit(&back_dec);
        Point2D p  = {.x = 3, .y = 4};
        bool    ok = StrAppendFmt(&out, "{}", p);
        ok         = ok && (ZstrCompare(StrBegin(&out), "(3, 4)") == 0);
    
        StrDeinit(&out);
        i32     count = 7;
        bool    ok    = StrAppendFmt(&out, "got {} hits at {}", count, p);
        ok            = ok && (ZstrCompare(StrBegin(&out), "got 7 hits at (-1, 2)") == 0);
    
        StrDeinit(&out);
    
        bool ok = StrAppendFmt(&out, "{}", src);
        Zstr in = StrBegin(&out);
        StrReadFmt(in, "{}", dst);
        ok = ok && (dst.x == src.x) && (dst.y == src.y);
        };
        bool ok = StrAppendFmt(&out, "{}", b);
        ok      = ok && (ZstrCompare(StrBegin(&out), "[(0, 0)..(10, 20)]") == 0);
    
        StrDeinit(&out);
    
        bool ok = StrAppendFmt(&out, "{}", src);
        Zstr in = StrBegin(&out);
        StrReadFmt(in, "{}", dst);
        };
        bool ok = StrAppendFmt(&out, "{}", r);
        ok      = ok && (ZstrCompare(StrBegin(&out), "42:[(0, 0)..(100, 50)]@(50, 25)") == 0);
    
        StrDeinit(&out);
    
        bool ok = StrAppendFmt(&out, "{}", src);
        Zstr in = StrBegin(&out);
        StrReadFmt(in, "{}", dst);
        // types and built-ins coexist in one IOFMT expansion.
        bool ok = StrAppendFmt(&out, "score={.1} region={} origin={}", score, region, origin);
        ok      = ok && (ZstrCompare(StrBegin(&out), "score=1.5 region=7:[(1, 2)..(3, 4)]@(2, 3) origin=(0, 0)") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&output, "Hello, world!");
        success = success && (ZstrCompare(StrBegin(&output), "Hello, world!") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{​{Hello}}");
        success = success && (ZstrCompare(StrBegin(&output), "{Hello}") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{​{{​{");
        success = success && (ZstrCompare(StrBegin(&output), "{​{") == 0);
    
        StrDeinit(&output);
        Zstr str = "Hello";
        StrAppendFmt(&output, "{}", str);
        success = success && (ZstrCompare(StrBegin(&output), "Hello") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{>10}", str);
        success = success && (ZstrCompare(StrBegin(&output), "     Hello") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{<10}", str);
        success = success && (ZstrCompare(StrBegin(&output), "Hello     ") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{^10}", str);
        success = success && (ZstrCompare(StrBegin(&output), "  Hello   ") == 0);
        StrClear(&output);
        Str s = StrInitFromZstr("World", &alloc);
        StrAppendFmt(&output, "{}", s);
        success = success && (ZstrCompare(StrBegin(&output), "World") == 0);
        StrDeinit(&s);
        i8 i8_val = -42;
        StrAppendFmt(&output, "{}", i8_val);
        success = success && (ZstrCompare(StrBegin(&output), "-42") == 0);
        StrClear(&output);
        i16 i16_val = -1234;
        StrAppendFmt(&output, "{}", i16_val);
        success = success && (ZstrCompare(StrBegin(&output), "-1234") == 0);
        StrClear(&output);
        i32 i32_val = -123456;
        StrAppendFmt(&output, "{}", i32_val);
        success = success && (ZstrCompare(StrBegin(&output), "-123456") == 0);
        StrClear(&output);
        i64 i64_val = -1234567890LL;
        StrAppendFmt(&output, "{}", i64_val);
        success = success && (ZstrCompare(StrBegin(&output), "-1234567890") == 0);
        StrClear(&output);
        u8 u8_val = 42;
        StrAppendFmt(&output, "{}", u8_val);
        success = success && (ZstrCompare(StrBegin(&output), "42") == 0);
        StrClear(&output);
        u16 u16_val = 1234;
        StrAppendFmt(&output, "{}", u16_val);
        success = success && (ZstrCompare(StrBegin(&output), "1234") == 0);
        StrClear(&output);
        u32 u32_val = 123456;
        StrAppendFmt(&output, "{}", u32_val);
        success = success && (ZstrCompare(StrBegin(&output), "123456") == 0);
        StrClear(&output);
        u64 u64_val = 1234567890ULL;
        StrAppendFmt(&output, "{}", u64_val);
        success = success && (ZstrCompare(StrBegin(&output), "1234567890") == 0);
        StrClear(&output);
        i8 i8_max = 127;
        StrAppendFmt(&output, "{}", i8_max);
        success = success && (ZstrCompare(StrBegin(&output), "127") == 0);
        StrClear(&output);
        i8 i8_min = -128;
        StrAppendFmt(&output, "{}", i8_min);
        success = success && (ZstrCompare(StrBegin(&output), "-128") == 0);
        StrClear(&output);
        u8 u8_max = 255;
        StrAppendFmt(&output, "{}", u8_max);
        success = success && (ZstrCompare(StrBegin(&output), "255") == 0);
        StrClear(&output);
        u8 u8_min = 0;
        StrAppendFmt(&output, "{}", u8_min);
        success = success && (ZstrCompare(StrBegin(&output), "0") == 0);
    
        StrDeinit(&output);
        u32 val = 0xDEADBEEF;
        StrAppendFmt(&output, "{x}", val);
        success = success && (ZstrCompare(StrBegin(&output), "0xdeadbeef") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{X}", val);
        success = success && (ZstrCompare(StrBegin(&output), "0xDEADBEEF") == 0);
    
        StrDeinit(&output);
        u8 val = 0xA5; // 10100101 in binary
        StrAppendFmt(&output, "{b}", val);
        success = success && (ZstrCompare(StrBegin(&output), "0b10100101") == 0);
    
        StrDeinit(&output);
        u16 val = 0777;
        StrAppendFmt(&output, "{o}", val);
        success = success && (ZstrCompare(StrBegin(&output), "0o777") == 0);
    
        StrDeinit(&output);
        f32 f32_val = 3.14159f;
        StrAppendFmt(&output, "{}", f32_val);
        success = success && (ZstrCompare(StrBegin(&output), "3.141590") == 0);
        StrClear(&output);
        f64 f64_val = 2.71828;
        StrAppendFmt(&output, "{}", f64_val);
        success = success && (ZstrCompare(StrBegin(&output), "2.718280") == 0);
    
        StrDeinit(&output);
    
        StrAppendFmt(&output, "{.2}", val);
        success = success && (ZstrCompare(StrBegin(&output), "3.14") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{.0}", val);
        success = success && (ZstrCompare(StrBegin(&output), "3") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{.10}", val);
        success = success && (ZstrCompare(StrBegin(&output), "3.1415926536") == 0);
    
        StrDeinit(&output);
        f64 pos_inf = F64_INFINITY;
        StrAppendFmt(&output, "{}", pos_inf);
        success = success && (ZstrCompare(StrBegin(&output), "inf") == 0);
        StrClear(&output);
        f64 neg_inf = -F64_INFINITY;
        StrAppendFmt(&output, "{}", neg_inf);
        success = success && (ZstrCompare(StrBegin(&output), "-inf") == 0);
        StrClear(&output);
        f64 nan_val = F64_NAN;
        StrAppendFmt(&output, "{}", nan_val);
        success = success && (ZstrCompare(StrBegin(&output), "nan") == 0);
    
        StrDeinit(&output);
        i32 val = 42;
        StrAppendFmt(&output, "{5}", val);
        success = success && (ZstrCompare(StrBegin(&output), "   42") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{<5}", val);
        success = success && (ZstrCompare(StrBegin(&output), "42   ") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{^5}", val);
        success = success && (ZstrCompare(StrBegin(&output), " 42  ") == 0);
        StrClear(&output);
        Zstr str = "abc";
        StrAppendFmt(&output, "{5}", str);
        success = success && (ZstrCompare(StrBegin(&output), "  abc") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{<5}", str);
        success = success && (ZstrCompare(StrBegin(&output), "abc  ") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{^5}", str);
        success = success && (ZstrCompare(StrBegin(&output), " abc ") == 0);
    
        StrDeinit(&output);
    
        StrAppendFmt(&output, "{} {} {}", hello, num, pi);
        success = success && (ZstrCompare(StrBegin(&output), "Hello 42 3.140000") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{} {} {}", pi, hello, num);
        success = success && (ZstrCompare(StrBegin(&output), "3.140000 Hello 42") == 0);
    
        StrDeinit(&output);
        Zstr mixed_case = "MiXeD CaSe";
        StrAppendFmt(&output, "{c}", mixed_case);
        success = success && (ZstrCompare(StrBegin(&output), "MiXeD CaSe") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", mixed_case);
        success = success && (ZstrCompare(StrBegin(&output), "mixed case") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", mixed_case);
        success = success && (ZstrCompare(StrBegin(&output), "MIXED CASE") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", s);
        success = success && (ZstrCompare(StrBegin(&output), "MiXeD CaSe") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", s);
        success = success && (ZstrCompare(StrBegin(&output), "mixed case") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", s);
        success = success && (ZstrCompare(StrBegin(&output), "MIXED CASE") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", upper_char);
        success = success && (ZstrCompare(StrBegin(&output), "M") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", upper_char);
        success = success && (ZstrCompare(StrBegin(&output), "m") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", lower_char);
        success = success && (ZstrCompare(StrBegin(&output), "M") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", u16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'A' && StrBegin(&output)[1] == 'B');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", u16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'a' && StrBegin(&output)[1] == 'b');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", u16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'A' && StrBegin(&output)[1] == 'B');
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", i16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'C' && StrBegin(&output)[1] == 'd');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", i16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'c' && StrBegin(&output)[1] == 'd');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", i16_value);
        success = success && (StrLen(&output) == 2 && StrBegin(&output)[0] == 'C' && StrBegin(&output)[1] == 'D');
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'E' && StrBegin(&output)[1] == 'f' &&
                              StrBegin(&output)[2] == 'G' && StrBegin(&output)[3] == 'h');
        StrClear(&output);
        StrAppendFmt(&output, "{c}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'E' && StrBegin(&output)[1] == 'f' &&
                              StrBegin(&output)[2] == 'G' && StrBegin(&output)[3] == 'h');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'e' && StrBegin(&output)[1] == 'f' &&
                              StrBegin(&output)[2] == 'g' && StrBegin(&output)[3] == 'h');
        StrClear(&output);
        StrAppendFmt(&output, "{a}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'e' && StrBegin(&output)[1] == 'f' &&
                              StrBegin(&output)[2] == 'g' && StrBegin(&output)[3] == 'h');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'E' && StrBegin(&output)[1] == 'F' &&
                              StrBegin(&output)[2] == 'G' && StrBegin(&output)[3] == 'H');
        StrClear(&output);
        StrAppendFmt(&output, "{A}", u32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'E' && StrBegin(&output)[1] == 'F' &&
                              StrBegin(&output)[2] == 'G' && StrBegin(&output)[3] == 'H');
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'I' && StrBegin(&output)[1] == 'j' &&
                              StrBegin(&output)[2] == 'K' && StrBegin(&output)[3] == 'l');
        StrClear(&output);
        StrAppendFmt(&output, "{c}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'I' && StrBegin(&output)[1] == 'j' &&
                              StrBegin(&output)[2] == 'K' && StrBegin(&output)[3] == 'l');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'i' && StrBegin(&output)[1] == 'j' &&
                              StrBegin(&output)[2] == 'k' && StrBegin(&output)[3] == 'l');
        StrClear(&output);
        StrAppendFmt(&output, "{a}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'i' && StrBegin(&output)[1] == 'j' &&
                              StrBegin(&output)[2] == 'k' && StrBegin(&output)[3] == 'l');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'I' && StrBegin(&output)[1] == 'J' &&
                              StrBegin(&output)[2] == 'K' && StrBegin(&output)[3] == 'L');
        StrClear(&output);
        StrAppendFmt(&output, "{A}", i32_value);
        success = success && (StrLen(&output) == 4 && StrBegin(&output)[0] == 'I' && StrBegin(&output)[1] == 'J' &&
                              StrBegin(&output)[2] == 'K' && StrBegin(&output)[3] == 'L');
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 't');
        StrAppendFmt(&output, "{c}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 't');
        StrClear(&output);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 't');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'm' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'o' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 's' && StrBegin(&output)[7] == 't');
        StrAppendFmt(&output, "{a}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'm' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'o' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 's' && StrBegin(&output)[7] == 't');
        StrClear(&output);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'm' && StrBegin(&output)[1] == 'n' &&
                              StrBegin(&output)[2] == 'o' && StrBegin(&output)[3] == 'p' && StrBegin(&output)[4] == 'q' &&
                              StrBegin(&output)[5] == 'r' && StrBegin(&output)[6] == 's' && StrBegin(&output)[7] == 't');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'N' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'P' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'R' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 'T');
        StrAppendFmt(&output, "{A}", u64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'N' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'P' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'R' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 'T');
        StrClear(&output);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'M' && StrBegin(&output)[1] == 'N' &&
                              StrBegin(&output)[2] == 'O' && StrBegin(&output)[3] == 'P' && StrBegin(&output)[4] == 'Q' &&
                              StrBegin(&output)[5] == 'R' && StrBegin(&output)[6] == 'S' && StrBegin(&output)[7] == 'T');
        StrClear(&output);
    
        StrAppendFmt(&output, "{c}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrAppendFmt(&output, "{c}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrClear(&output);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrClear(&output);
    
        StrAppendFmt(&output, "{a}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'u' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'w' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrAppendFmt(&output, "{a}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'u' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'w' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrClear(&output);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'u' && StrBegin(&output)[1] == 'v' &&
                              StrBegin(&output)[2] == 'w' && StrBegin(&output)[3] == 'x' && StrBegin(&output)[4] == 'y' &&
                              StrBegin(&output)[5] == 'z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrClear(&output);
    
        StrAppendFmt(&output, "{A}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'V' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'X' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'Z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        StrAppendFmt(&output, "{A}", i64_value);
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'V' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'X' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'Z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
        success = success && (StrLen(&output) == 8 && StrBegin(&output)[0] == 'U' && StrBegin(&output)[1] == 'V' &&
                              StrBegin(&output)[2] == 'W' && StrBegin(&output)[3] == 'X' && StrBegin(&output)[4] == 'Y' &&
                              StrBegin(&output)[5] == 'Z' && StrBegin(&output)[6] == '1' && StrBegin(&output)[7] == '2');
    
        StrDeinit(&output);
        BitVec bv1 = BitVecFromStr("10110", alloc_base);
        StrAppendFmt(&output, "{}", bv1);
        success = success && (ZstrCompare(StrBegin(&output), "10110") == 0);
        StrClear(&output);
        BitVec bv2 = BitVecFromInteger(0xABCD, 16, alloc_base);
        StrAppendFmt(&output, "{x}", bv2);
        success = success && (ZstrCompare(StrBegin(&output), "0xabcd") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{X}", bv2);
        success = success && (ZstrCompare(StrBegin(&output), "0xABCD") == 0);
        StrClear(&output);
        BitVec bv3 = BitVecFromInteger(0755, 10, alloc_base);
        StrAppendFmt(&output, "{o}", bv3);
        success = success && (ZstrCompare(StrBegin(&output), "0o755") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{>10}", bv1);
        success = success && (ZstrCompare(StrBegin(&output), "     10110") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{<10}", bv1);
        success = success && (ZstrCompare(StrBegin(&output), "10110     ") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{^10}", bv1);
        success = success && (ZstrCompare(StrBegin(&output), "  10110   ") == 0);
        StrClear(&output);
        BitVec bv_zero = BitVecFromInteger(0, 1, alloc_base);
        StrAppendFmt(&output, "{x}", bv_zero);
        success = success && (ZstrCompare(StrBegin(&output), "0x0") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{o}", bv_zero);
        success = success && (ZstrCompare(StrBegin(&output), "0o0") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{}", big_dec);
        success = success && (ZstrCompare(StrBegin(&output), "123456789012345678901234567890") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{x}", hex_val);
        success = success && (ZstrCompare(StrBegin(&output), "deadbeefcafebabe1234") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{X}", hex_val);
        success = success && (ZstrCompare(StrBegin(&output), "DEADBEEFCAFEBABE1234") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{b}", bin_val);
        success = success && (ZstrCompare(StrBegin(&output), "10100011") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{o}", oct_val);
        success = success && (ZstrCompare(StrBegin(&output), "755") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{>34}", big_dec);
        success = success && (ZstrCompare(StrBegin(&output), "    123456789012345678901234567890") == 0);
    
        IntDeinit(&big_dec);
    
        StrAppendFmt(&output, "{}", exact);
        success = success && (ZstrCompare(StrBegin(&output), "1234567890.012345") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{e}", sci);
        success = success && (ZstrCompare(StrBegin(&output), "1.234567e+04") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{E}", sci);
        success = success && (ZstrCompare(StrBegin(&output), "1.234567E+04") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{.3}", short_v);
        success = success && (ZstrCompare(StrBegin(&output), "1.200") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{>18}", sci);
        success = success && (ZstrCompare(StrBegin(&output), "          12345.67") == 0);
    
        FloatDeinit(&exact);
        StrAppendFmt(&s, "old prefix ");
        StrWriteFmt(&s, "fresh {}", LVAL(42));
        bool ok = (StrLen(&s) == 8) && (StrBegin(&s)[0] == 'f') && (StrBegin(&s)[StrLen(&s) - 1] == '2');
        StrDeinit(&s);
        DefaultAllocatorDeinit(&alloc);
        bool ok            = StrPatchFmt(&s, 2, "{}", LVAL(1234));
        ok                 = ok && StrLen(&s) == before_length;
        ok                 = ok && StrBegin(&s)[0] == 'A' && StrBegin(&s)[1] == 'A';
        ok = ok && StrBegin(&s)[2] == '1' && StrBegin(&s)[3] == '2' && StrBegin(&s)[4] == '3' && StrBegin(&s)[5] == '4';
        ok = ok && StrBegin(&s)[6] == 'A' && StrBegin(&s)[7] == 'A';
        ok                 = ok && StrLen(&s) == before_length;
        ok                 = ok && StrBegin(&s)[0] == 'A' && StrBegin(&s)[1] == 'A';
        ok = ok && StrBegin(&s)[2] == '1' && StrBegin(&s)[3] == '2' && StrBegin(&s)[4] == '3' && StrBegin(&s)[5] == '4';
        ok = ok && StrBegin(&s)[6] == 'A' && StrBegin(&s)[7] == 'A';
        ok                 = ok && StrBegin(&s)[0] == 'A' && StrBegin(&s)[1] == 'A';
        ok = ok && StrBegin(&s)[2] == '1' && StrBegin(&s)[3] == '2' && StrBegin(&s)[4] == '3' && StrBegin(&s)[5] == '4';
        ok = ok && StrBegin(&s)[6] == 'A' && StrBegin(&s)[7] == 'A';
    
        // Patch that would extend past the end must fail.
        ok = ok && !StrPatchFmt(&s, 6, "{}", LVAL(9999));
        ok = ok && StrLen(&s) == before_length;
        ok = ok && StrBegin(&s)[6] == 'A' && StrBegin(&s)[7] == 'A';
    
        StrDeinit(&s);
        StrAppendFmt(&output, "{}", b); // Buf is a first-class {} argument now
    
        bool ok = ZstrCompare(StrBegin(&output), "hello") == 0;
    
        BufDeinit(&b);
        u8 esc = 0x1B;
        StrAppendFmt(&out, "{c}", esc);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x1b") == 0);
        StrClear(&out);
        u8 bel = 0x07;
        StrAppendFmt(&out, "{c}", bel);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x07") == 0);
        StrClear(&out);
        u8 hi = 0xFF;
        StrAppendFmt(&out, "{A}", hi);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xFF") == 0);
        StrClear(&out);
        u8 ab = 0xAB;
        StrAppendFmt(&out, "{c}", ab);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xab") == 0);
    
        StrDeinit(&out);
        StrClear(&s);
        StrAppendFmt(&s, "{}", utc);
        ok = ok && ZstrCompare(StrBegin(&s), "2021-01-01T00:00:00Z") == 0;
    
        DateTime ist = DateTimeFromUnixNs(base, 19800); // +05:30
        StrClear(&s);
        StrAppendFmt(&s, "{}", ist);
        ok = ok && ZstrCompare(StrBegin(&s), "2021-01-01T05:30:00+05:30") == 0;
    
        DateTime neg = DateTimeFromUnixNs(base, -34200); // -09:30
        StrClear(&s);
        StrAppendFmt(&s, "{}", neg);
        ok = ok && ZstrCompare(StrBegin(&s), "2020-12-31T14:30:00-09:30") == 0;
    
        DateTime frac = DateTimeFromUnixNs(base + 123456789ull, 0);
        StrClear(&s);
        StrAppendFmt(&s, "{}", frac);
        ok = ok && ZstrCompare(StrBegin(&s), "2021-01-01T00:00:00.123456789Z") == 0;
    
        StrDeinit(&s);
    
        Str  text = FloatToStr(&f);
        bool ok   = (ZstrCompare(StrBegin(&text), expected) == 0);
    
        StrDeinit(&text);
            Str back = StrInit(&alloc);
            FileRead(&f, &back);
            ok = (ZstrCompare(StrBegin(&back), expect) == 0);
            StrDeinit(&back);
            FileClose(&f);
        // of the whole buffer, so the prefix "AB" rides along: "   ABxyz". A wrong
        // start_len / sub->add mis-computes content_len and changes the pad count.
        ok = ok && (ZstrCompare(StrBegin(&output), "   ABxyz") == 0);
    
        StrDeinit(&s);
        Str s = StrInitFromZstr("hi", &alloc);
        StrAppendFmt(&output, "{<5}", s);
        ok = ok && (ZstrCompare(StrBegin(&output), "hi   ") == 0);
    
        StrDeinit(&s);
    
        StrAppendFmt(&output, "{X}", s);
        ok = ok && (ZstrCompare(StrBegin(&output), "0x0F") == 0);
    
        StrDeinit(&s);
    
        StrAppendFmt(&output, "{x}", s);
        ok = ok && (ZstrCompare(StrBegin(&output), "0x0f") == 0);
    
        StrDeinit(&s);
        StrAppendFmt(&output, "{x}", s);
        // gt_to_ge => " 0x01 0x02" (leading space); gt_to_le => "0x010x02".
        ok = ok && (ZstrCompare(StrBegin(&output), "0x01 0x02") == 0);
    
        StrDeinit(&s);
    
        StrAppendFmt(&output, "{x}", s);
        ok = ok && (ZstrCompare(StrBegin(&output), "0x05") == 0);
    
        StrDeinit(&s);
        Str s = StrInitFromZstr("hello", &alloc);
        StrAppendFmt(&output, "{.3}", s);
        ok = ok && (ZstrCompare(StrBegin(&output), "hel") == 0);
    
        StrDeinit(&s);
        Zstr s = "AB"; // 0x41 0x42
        StrAppendFmt(&output, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0x41 0x42") == 0);
    
        StrDeinit(&output);
        Zstr s = "Z"; // 0x5a
        StrAppendFmt(&output, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0x5a") == 0);
    
        StrDeinit(&output);
        Zstr s = "\xab"; // single byte 0xab
        StrAppendFmt(&output, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0xab") == 0);
    
        StrDeinit(&output);
        Zstr s = "\xab";
        StrAppendFmt(&output, "{X}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0xAB") == 0);
    
        StrDeinit(&output);
        Zstr s = "\x05"; // single byte 0x05
        StrAppendFmt(&output, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0x05") == 0);
    
        StrDeinit(&output);
        Zstr s = "\xfe";
        StrAppendFmt(&output, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "0xfe") == 0);
    
        StrDeinit(&output);
        Zstr s = "Hello";
        StrAppendFmt(&output, "{.3}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "Hel") == 0);
    
        StrDeinit(&output);
        Zstr s = "Hi";
        StrAppendFmt(&output, "{.10}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "Hi") == 0);
    
        StrDeinit(&output);
        Zstr s = "Hello";
        StrAppendFmt(&output, "{.1}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "H") == 0);
    
        StrDeinit(&output);
        Zstr s = "Hi";
        StrAppendFmt(&output, "abc{>10}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "        abcHi") == 0);
    
        StrDeinit(&output);
        Zstr s = "Hi";
        StrAppendFmt(&output, "xy{<10}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "xyHi        ") == 0);
    
        StrDeinit(&output);
        Zstr s = "";
        StrAppendFmt(&output, "{>5}", s);
        bool ok = (ZstrCompare(StrBegin(&output), "     ") == 0);
    
        StrDeinit(&output);
    
        StrAppendFmt(&output, "{e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1e+00") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&output, "{.0e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "0e+00") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&output, "{.3e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "0.000e+00") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&output, "{.2e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.20e+01") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&output, "{e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.234567e+04") == 0);
        StrClear(&output);
    
        StrAppendFmt(&output, "{E}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.234567E+04") == 0);
    
        FloatDeinit(&v);
    
        Str text = FloatToStr(&val);
        success  = success && (ZstrCompare(StrBegin(&text), "3.5") == 0);
        StrDeinit(&text);
    
        Str text = FloatToStr(&val);
        success  = success && (ZstrCompare(StrBegin(&text), "12.25") == 0);
        StrDeinit(&text);
        // 1.5e2 == 150
        Str text = FloatToStr(&val);
        success  = success && (ZstrCompare(StrBegin(&text), "150") == 0);
        StrDeinit(&text);
    
        Str text = FloatToStr(&val);
        success  = success && (ZstrCompare(StrBegin(&text), "-0.25") == 0);
        StrDeinit(&text);
    
        StrAppendFmt(&out, "{05}", (u32)42);
        ok = ok && (ZstrCompare(StrBegin(&out), "00042") == 0);
        ok = ok && (StrLen(&out) == 5);
    
        StrAppendFmt(&out, "{05}", (u32)12345);
        ok = ok && (ZstrCompare(StrBegin(&out), "12345") == 0);
        ok = ok && (StrLen(&out) == 5);
    
        StrAppendFmt(&out, "{06}", (i32)-42);
        ok = ok && (ZstrCompare(StrBegin(&out), "-00042") == 0);
        ok = ok && (StrLen(&out) == 6);
    
        StrAppendFmt(&out, "{05}", (i32)42);
        ok = ok && (ZstrCompare(StrBegin(&out), "00042") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{08}", (i32)-7);
        ok = ok && (ZstrCompare(StrBegin(&out), "-0000007") == 0);
        ok = ok && (StrLen(&out) == 8);
    
        StrAppendFmt(&out, "{016x}", (u32)0xFF);
        ok = ok && (ZstrCompare(StrBegin(&out), "00000000000000ff") == 0);
        ok = ok && (StrLen(&out) == 16);
        Str out;
        success = success && float_try_to_decimal_str(&out, &val, 3, true, alloc_base);
        success = success && (ZstrCompare(StrBegin(&out), "12.000") == 0);
        StrDeinit(&out);
        Str out;
        success = success && float_try_to_decimal_str(&out, &val, 0, true, alloc_base);
        success = success && (ZstrCompare(StrBegin(&out), "12") == 0);
        StrDeinit(&out);
        Str out;
        success = success && float_try_to_decimal_str(&out, &val, 3, true, alloc_base);
        success = success && (ZstrCompare(StrBegin(&out), "1.500") == 0);
        StrDeinit(&out);
        Str out;
        success = success && float_try_to_decimal_str(&out, &val, 0, true, alloc_base);
        success = success && (ZstrCompare(StrBegin(&out), "1") == 0);
        StrDeinit(&out);
        Str out;
        success = success && float_try_to_decimal_str(&out, &val, 1, true, alloc_base);
        success = success && (ZstrCompare(StrBegin(&out), "1.2") == 0);
        StrDeinit(&out);
        f64 v = 1.5;
        StrAppendFmt(&output, "{}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.500000") == 0);
    
        StrDeinit(&output);
        f64 v = 1.5;
        StrAppendFmt(&output, "{e}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.500000e+00") == 0);
    
        StrDeinit(&output);
        f64 v = 1.5;
        StrAppendFmt(&output, "{E}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "1.500000E+00") == 0);
    
        StrDeinit(&output);
        f64 v = 1.5;
        StrAppendFmt(&output, "{12}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "    1.500000") == 0);
        ok = ok && (StrLen(&output) == 12);
        f64 v = 1.5;
        StrAppendFmt(&output, "{12}", v);
        ok = ok && (ZstrCompare(StrBegin(&output), "    XYZ1.500000") == 0);
    
        StrDeinit(&output);
    
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1e+00") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1e-03") == 0);
    
        FloatDeinit(&v);
    
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1e+12") == 0);
    
        FloatDeinit(&v);
        // Real: lowercase hex "0xff". base->42 mutant fails (not "0xff");
        // and_to_or mutant would force caps -> "0xFF".
        bool ok = (ZstrCompare(StrBegin(&out), "0xff") == 0);
    
        StrDeinit(&out);
        StrAppendFmt(&out, "{X}", v);
        // Real: uppercase hex "0xFF". ne_to_eq mutant inverts caps -> "0xff".
        bool ok = (ZstrCompare(StrBegin(&out), "0xFF") == 0);
    
        StrDeinit(&out);
        i64 v = 5; // 0b101
        StrAppendFmt(&out, "{b}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "0b101") == 0);
    
        StrDeinit(&out);
        i64 v = 8; // 0o10
        StrAppendFmt(&out, "{o}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "0o10") == 0);
    
        StrDeinit(&out);
        i64 v = -42;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "-42") == 0);
    
        StrDeinit(&out);
        i64 v = 42;
        StrAppendFmt(&out, "X{5}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "   X42") == 0);
    
        StrDeinit(&out);
        StrAppendFmt(&out, "X{05}", v);
        // start_len=1, content "42" len 2, width 5 -> three '0' fills: "X00042".
        bool ok = (ZstrCompare(StrBegin(&out), "X00042") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&output, "{c}", a);
        success = (ZstrCompare(StrBegin(&output), "A") == 0);
    
        IntDeinit(&a);
    
        StrAppendFmt(&output, "{c}", a);
        success = (ZstrCompare(StrBegin(&output), "z") == 0);
    
        IntDeinit(&a);
        StrAppendFmt(&output, "ab");
        StrAppendFmt(&output, "{>6}", seven);
        success = (ZstrCompare(StrBegin(&output), "     ab7") == 0);
    
        IntDeinit(&seven);
        u8   v  = 200;
        bool ok = StrAppendFmt(&out, "{1r}", v);
        ok      = ok && (ZstrCompare(StrBegin(&out), "200") == 0);
    
        StrDeinit(&out);
        u16  v  = 258;
        bool ok = StrAppendFmt(&out, "{2r}", v);
        ok      = ok && (ZstrCompare(StrBegin(&out), "258") == 0);
    
        StrDeinit(&out);
        u32  v  = 65538;
        bool ok = StrAppendFmt(&out, "{4r}", v);
        ok      = ok && (ZstrCompare(StrBegin(&out), "65538") == 0);
    
        StrDeinit(&out);
        u64  v  = 4294967298ULL;
        bool ok = StrAppendFmt(&out, "{8r}", v);
        ok      = ok && (ZstrCompare(StrBegin(&out), "4294967298") == 0);
    
        StrDeinit(&out);
        i64  v  = 4294967298LL;
        bool ok = StrAppendFmt(&out, "{8r}", v);
        ok      = ok && (ZstrCompare(StrBegin(&out), "4294967298") == 0);
    
        StrDeinit(&out);
        // the "X:" prefix rides along after the spaces: "     X:255" (len 10).
        StrAppendFmt(&out, "{8}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "     X:255") == 0);
    
        StrDeinit(&out);
        u64 v = 7;
        StrAppendFmt(&out, "{5}", v); // "    7"
        ok = ok && (ZstrCompare(StrBegin(&out), "    7") == 0);
        StrClear(&out);
        // Left-align variant so a dropped pad is unambiguous.
        StrAppendFmt(&out, "{<5}", v); // "7    "
        ok = ok && (ZstrCompare(StrBegin(&out), "7    ") == 0);
    
        StrDeinit(&out);
        u64 v = 42;
        StrAppendFmt(&out, "{05}", v); // zero-pad width 5 -> "00042"
        ok = ok && (ZstrCompare(StrBegin(&out), "p00042") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{e}", v);
        bool ok = ZstrCompare(StrBegin(&out), "1.234567e+04") == 0;
    
        FloatDeinit(&v);
    
        StrAppendFmt(&out, "{.2e}", v);
        bool ok = ZstrCompare(StrBegin(&out), "1.23e+04") == 0;
    
        FloatDeinit(&v);
        StrAppendFmt(&out, "XX");
        StrAppendFmt(&out, "{>5}", v);
        bool ok = ZstrCompare(StrBegin(&out), "  XX1.2") == 0 && StrLen(&out) == 7;
    
        FloatDeinit(&v);
    
        StrAppendFmt(&out, "XX{>5}", bv);
        bool ok = (StrLen(&out) == 7) && (ZstrCompare(StrBegin(&out), "    XX1") == 0);
    
        BitVecDeinit(&bv);
        bool r = StrPatchFmt(&o, 0, "AB{");
    
        bool ok = (r == false) && (ZstrCompare(StrBegin(&o), "-----") == 0);
    
        StrDeinit(&o);
        bool r = StrPatchFmt(&o, StrLen(&o), ""); // offset == length, empty render
    
        bool ok = (r == true) && (ZstrCompare(StrBegin(&o), "hello") == 0);
    
        StrDeinit(&o);
        bool r = StrPatchFmt(&o, 0, "12345");                      // renders exactly 5 chars
    
        bool ok = (r == true) && (ZstrCompare(StrBegin(&o), "12345") == 0);
    
        StrDeinit(&o);
    
        Str  oct_text = IntToOctStr(&oct);
        bool ok       = (ZstrCompare(StrBegin(&oct_text), "7") == 0);
    
        StrDeinit(&oct_text);
        StrAppendFmt(&output, "{s}", ZstrIO(name, alloc_base));
    
        bool ok = (ZstrCompare(StrBegin(&output), "hello") == 0);
    
        StrDeinit(&output);
        StrAppendFmt(&output, "{c}", v);
    
        bool ok = (StrLen(&output) == 1) && (StrBegin(&output)[0] == 'Q');
    
        StrDeinit(&output);
        StrAppendFmt(&output, "{c}", v);
    
        bool ok = (StrLen(&output) == 4) && (ZstrCompare(StrBegin(&output), "BCDE") == 0);
    
        StrDeinit(&output);
        StrPushBackR(&src, 0x1A);
        StrAppendFmt(&out, "{c}", src);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x1a") == 0);
        StrClear(&out);
        StrClear(&src);
        StrPushBackR(&src, 0xA1);
        StrAppendFmt(&out, "{c}", src);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xa1") == 0);
    
        StrDeinit(&src);
        Float f = FloatFromStr("1.2", alloc_base);
        StrAppendFmt(&out, "{.5}", f);
        ok = ok && (ZstrCompare(StrBegin(&out), "1.20000") == 0);
        StrClear(&out);
        Float g = FloatFromStr("3.14", alloc_base);
        StrAppendFmt(&out, "{.6}", g);
        ok = ok && (ZstrCompare(StrBegin(&out), "3.140000") == 0);
    
        FloatDeinit(&f);
        u32 v = 255;
        StrAppendFmt(&out, "{03}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "255") == 0);
        StrClear(&out);
        // Sanity: width one wider really does pad (guards against a no-op pad).
        StrAppendFmt(&out, "{04}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "0255") == 0);
    
        StrDeinit(&out);
        Zstr s = "abc";
        StrAppendFmt(&out, "{3}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "abc") == 0);
        StrClear(&out);
        // Left/center at the exact boundary likewise add nothing.
        StrAppendFmt(&out, "{<3}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "abc") == 0);
        StrClear(&out);
    
        StrAppendFmt(&out, "{^3}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "abc") == 0);
        StrClear(&out);
        // Sanity: width 4 does pad (one space, right-aligned default).
        StrAppendFmt(&out, "{4}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), " abc") == 0);
    
        StrDeinit(&out);
        ok          = ok && StrPatchFmt(&s, 2, "{}", LVAL(1234));
        ok          = ok && (StrLen(&s) == before);
        ok          = ok && StrBegin(&s)[2] == '1' && StrBegin(&s)[5] == '4';
    
        StrDeinit(&s);
        Str s = StrInitFromZstr("hello", &alloc);
        StrAppendFmt(&out, "{}", s); // width defaults to 0 -> no padding
        ok = ok && (ZstrCompare(StrBegin(&out), "hello") == 0);
    
        StrDeinit(&s);
        f64 v = 3.14;
        StrAppendFmt(&out, "{}", v); // default precision 6
        ok = ok && (ZstrCompare(StrBegin(&out), "3.140000") == 0);
        StrClear(&out);
    
        StrAppendFmt(&out, "{.2}", v); // explicit precision 2
        ok = ok && (ZstrCompare(StrBegin(&out), "3.14") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{05}", (u32)7);
        ok = ok && (ZstrCompare(StrBegin(&out), "00007") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{007}", (u32)3);
        ok = ok && (ZstrCompare(StrBegin(&out), "0000003") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{09}", (u32)3);
        ok = ok && (ZstrCompare(StrBegin(&out), "000000003") == 0);
    
        StrDeinit(&out);
    
        StrAppendFmt(&out, "{9}", (u32)3);
        ok = ok && (ZstrCompare(StrBegin(&out), "        3") == 0);
        ok = ok && (StrLen(&out) == 9);
        bool rc = StrAppendFmt(&out, "{.9s}", s);
        ok      = ok && rc;
        ok      = ok && (ZstrCompare(StrBegin(&out), "Hello") == 0);
    
        StrDeinit(&out);
        u32              v     = 7;
        StrAppendFmt(&out, "{05}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "00007") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        Zstr             s     = "ab";
        StrAppendFmt(&out, "{4}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "  ab") == 0);
        StrClear(&out);
        // Two-digit width exercises the width loop (151) more than once.
        // Two-digit width exercises the width loop (151) more than once.
        StrAppendFmt(&out, "{12}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "          ab") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        f64              v     = 3.14159;
        StrAppendFmt(&out, "{.2}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "3.14") == 0);
        StrClear(&out);
        // multi-digit precision exercises the precision loop body (165).
        // multi-digit precision exercises the precision loop body (165).
        StrAppendFmt(&out, "{.4}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "3.1416") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        bool rc = StrAppendFmt(&out, "{.}", v);
        // Real: false; output keeps only the prior "literal" (append stopped).
        bool ok = (rc == false) && (ZstrCompare(StrBegin(&out), "literal") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        i32              v     = -7;
        StrAppendFmt(&out, "{05}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "-0007") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        u32              v     = 123;
        StrAppendFmt(&out, "{03}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "123") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{05}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{05}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "00123") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        Zstr             s     = "abc";
        StrAppendFmt(&out, "{3}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "abc") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "  abc") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        Str              out   = StrInit(&alloc);
        StrAppendFmt(&out, "a{​{b");
        bool ok = (ZstrCompare(StrBegin(&out), "a{b") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        Str              out   = StrInit(&alloc);
        StrAppendFmt(&out, "a}}b");
        bool ok = (ZstrCompare(StrBegin(&out), "a}b") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        u32              v     = 0xAB;
        StrAppendFmt(&out, "{x}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "0xab") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        u16              v     = 0x1234; // 4660
        bool             rc    = StrAppendFmt(&out, "{<2r}", v);
        bool             ok    = rc && (ZstrCompare(StrBegin(&out), "4660") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        u64              v     = 0x0102030405060708ULL; // 72623859790382856
        bool             rc    = StrAppendFmt(&out, "{>8r}", v);
        bool             ok    = rc && (ZstrCompare(StrBegin(&out), "72623859790382856") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
            ok = ok && FWriteFmtLn(&f, "n={}", LVAL((i32)42));
            FileClose(&f);
            File r = FileOpen(StrBegin(&path), "r");
            if (FileIsOpen(&r)) {
                Str back = StrInit(&alloc);
                Str back = StrInit(&alloc);
                FileRead(&r, &back);
                ok = ok && (ZstrCompare(StrBegin(&back), "n=42\n") == 0);
                StrDeinit(&back);
                FileClose(&r);
            ok = ok && FWriteFmt(&f, "X");
            FileClose(&f);
            File r = FileOpen(StrBegin(&path), "r");
            if (FileIsOpen(&r)) {
                Str back = StrInit(&alloc);
                Str back = StrInit(&alloc);
                FileRead(&r, &back);
                ok = ok && (ZstrCompare(StrBegin(&back), "X") == 0);
                StrDeinit(&back);
                FileClose(&r);
        StrPushBackR(&s, (char)0x4F); // multi-digit so StrLen(&hex)!=1 path
        StrAppendFmt(&out, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "0x01 0x4f") == 0);
        StrDeinit(&s);
        return ok && dbg_no_leak(&dbg, &out);
        StrPushBackR(&s, (char)0x05);
        StrAppendFmt(&out, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "0x05") == 0);
        StrDeinit(&s);
        return ok && dbg_no_leak(&dbg, &out);
        Zstr s = "\x01\x4f";
        StrAppendFmt(&out, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "0x01 0x4f") == 0);
        return ok && dbg_no_leak(&dbg, &out);
    }
        Zstr s = "\x05";
        StrAppendFmt(&out, "{x}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "0x05") == 0);
        return ok && dbg_no_leak(&dbg, &out);
    }
        Str              s     = StrInitFromZstr("hi", &alloc);
        StrAppendFmt(&out, "{}", s); // width 0 default
        bool ok = (ZstrCompare(StrBegin(&out), "hi") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "   hi") == 0);
        StrDeinit(&s);
        StrDeinit(&out);
        Zstr             s     = "hi";
        StrAppendFmt(&out, "{}", s);
        bool ok = (ZstrCompare(StrBegin(&out), "hi") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        StrClear(&out);
        StrAppendFmt(&out, "{5}", s);
        ok = ok && (ZstrCompare(StrBegin(&out), "   hi") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        u64 v = 1234567890ULL;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1234567890") == 0);
        return ok && dbg_no_leak(&dbg, &out);
    }
        i64 v = -1234567890LL;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "-1234567890") == 0);
        return ok && dbg_no_leak(&dbg, &out);
    }
        u64              v     = 42;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "42") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "    42") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        i64              v     = -42;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "-42") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "   -42") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        MemCopy(&v, &bits, sizeof(v));
        StrAppendFmt(&out, "{c}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "ABCDEFGH") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        f64              ninf  = -F64_INFINITY;
        StrAppendFmt(&out, "{}", ninf);
        bool ok = (ZstrCompare(StrBegin(&out), "-inf") == 0);
        StrClear(&out);
        f64 pinf = F64_INFINITY;
        f64 pinf = F64_INFINITY;
        StrAppendFmt(&out, "{}", pinf);
        ok = ok && (ZstrCompare(StrBegin(&out), "inf") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        f64              v     = 1.5;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1.500000") == 0);
        StrClear(&out);
        // explicit precision 2 to contrast.
        // explicit precision 2 to contrast.
        StrAppendFmt(&out, "{.2}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "1.50") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        f64 v = 2.71828;
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "2.718280") == 0);
        return ok && dbg_no_leak(&dbg, &out);
    }
        f64              v     = 1.5;
        StrAppendFmt(&out, "{.1}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1.5") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6.1}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{6.1}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "   1.5") == 0);
        StrDeinit(&out);
        DefaultAllocatorDeinit(&alloc);
        Float            v     = FloatFromStr("12345.67", ab);
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1.234567e+04") == 0);
        StrClear(&out);
        Float w = FloatFromStr("0.001234", ab);
        Float w = FloatFromStr("0.001234", ab);
        StrAppendFmt(&out, "{e}", w);
        ok = ok && (ZstrCompare(StrBegin(&out), "1.234e-03") == 0);
        FloatDeinit(&v);
        FloatDeinit(&w);
        Float            v     = FloatFromStr("1.0", ab);
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1e+00") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        Float            v     = FloatFromStr("2.0", ab);
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "2e+00") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        Float v = FloatFromStr("1234567890.012345", &dbg.base);
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1234567890.012345") == 0);
        FloatDeinit(&v);
        return ok && dbg_no_leak(&dbg, &out);
        Float            v     = FloatFromStr("3.14159", ab);
        StrAppendFmt(&out, "{.2}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "3.14") == 0);
        StrClear(&out);
        // precision longer than frac pads with zeros.
        // precision longer than frac pads with zeros.
        StrAppendFmt(&out, "{.8}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "3.14159000") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        Float            v     = FloatFromStr("5", ab);
        StrAppendFmt(&out, "{.3}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "5.000") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        Float v = FloatFromStr("12345.67", &dbg.base);
        StrAppendFmt(&out, "{e}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1.234567e+04") == 0);
        FloatDeinit(&v);
        return ok && dbg_no_leak(&dbg, &out);
        Float            v     = FloatFromStr("1.5", ab);
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "1.5") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "   1.5") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        StrAppendFmt(&out, "AB");
        StrAppendFmt(&out, "{>6}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "   AB1.5") == 0);
        FloatDeinit(&v);
        StrDeinit(&out);
        BitVec bv = BitVecFromStr("10110", &dbg.base);
        StrAppendFmt(&out, "{}", bv);
        bool ok = (ZstrCompare(StrBegin(&out), "10110") == 0);
        BitVecDeinit(&bv);
        return ok && dbg_no_leak(&dbg, &out);
        BitVec           bv    = BitVecFromStr("101", ab);
        StrAppendFmt(&out, "{}", bv);
        bool ok = (ZstrCompare(StrBegin(&out), "101") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", bv);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", bv);
        ok = ok && (ZstrCompare(StrBegin(&out), "   101") == 0);
        BitVecDeinit(&bv);
        StrDeinit(&out);
        Int v = IntFromStr("123456789012345678901234567890", &dbg.base);
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "123456789012345678901234567890") == 0);
        IntDeinit(&v);
        return ok && dbg_no_leak(&dbg, &out);
        Int              v     = IntFrom(42, ab);
        StrAppendFmt(&out, "{}", v);
        bool ok = (ZstrCompare(StrBegin(&out), "42") == 0);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        StrClear(&out);
        StrAppendFmt(&out, "{6}", v);
        ok = ok && (ZstrCompare(StrBegin(&out), "    42") == 0);
        IntDeinit(&v);
        StrDeinit(&out);
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("Input: '{}', Output: '", in);
            for (size i = 0; i < StrLen(&result); i++) {
                WriteFmt("{c}", StrBegin(&result)[i]);
            }
            WriteFmt("'\n");
        StrReadFmt(z, "{}", bv1);
        Str result1 = BitVecToStr(&bv1);
        success     = success && (ZstrCompare(StrBegin(&result1), "10110") == 0);
        WriteFmt(
            "Test 1 - Binary: {}, Success: {}\n",
            "Test 1 - Binary: {}, Success: {}\n",
            result1,
            (ZstrCompare(StrBegin(&result1), "10110") == 0) ? "true" : "false"
        );
        StrDeinit(&result1);
        StrReadFmt(z, "{}", bv4);
        Str result4 = BitVecToStr(&bv4);
        success     = success && (ZstrCompare(StrBegin(&result4), "1101") == 0);
        WriteFmt(
            "Test 4 - Whitespace: {}, Success: {}\n",
            "Test 4 - Whitespace: {}, Success: {}\n",
            result4,
            (ZstrCompare(StrBegin(&result4), "1101") == 0) ? "true" : "false"
        );
        StrDeinit(&result4);
        StrReadFmt(z, "{}", bv5);
        Str result5 = BitVecToStr(&bv5);
        success     = success && (ZstrCompare(StrBegin(&result5), "0") == 0);
        WriteFmt(
            "Test 5 - Zero: {}, Success: {}\n",
            "Test 5 - Zero: {}, Success: {}\n",
            result5,
            (ZstrCompare(StrBegin(&result5), "0") == 0) ? "true" : "false"
        );
        StrDeinit(&result5);
        StrReadFmt(z, "{}", dec);
        dec_text = IntToStr(&dec);
        success  = success && (ZstrCompare(StrBegin(&dec_text), "123456789012345678901234567890") == 0);
    
        z = "deadbeefcafebabe1234";
        StrReadFmt(z, "{x}", hex);
        hex_text = IntToHexStr(&hex);
        success  = success && (ZstrCompare(StrBegin(&hex_text), "deadbeefcafebabe1234") == 0);
    
        z = "10100011";
        StrReadFmt(z, "{b}", bin);
        bin_text = IntToBinary(&bin);
        success  = success && (ZstrCompare(StrBegin(&bin_text), "10100011") == 0);
    
        z = "755";
        StrReadFmt(z, "{o}", oct);
        oct_text = IntToOctStr(&oct);
        success  = success && (ZstrCompare(StrBegin(&oct_text), "755") == 0);
    
        StrDeinit(&dec_text);
        StrReadFmt(z, "{}", dec);
        dec_text = FloatToStr(&dec);
        success  = success && (ZstrCompare(StrBegin(&dec_text), "1234567890.012345") == 0);
    
        z = "1.234567e+04";
        StrReadFmt(z, "{e}", sci);
        sci_text = FloatToStr(&sci);
        success  = success && (ZstrCompare(StrBegin(&sci_text), "12345.67") == 0);
    
        z = "-0.00125";
        StrReadFmt(z, "{}", neg);
        neg_text = FloatToStr(&neg);
        success  = success && (ZstrCompare(StrBegin(&neg_text), "-0.00125") == 0);
    
        StrDeinit(&dec_text);
    
        bool ok = StrAppendFmt(&out, "}}");
        ok      = ok && (ZstrCompare(StrBegin(&out), "}") == 0);
    
        StrDeinit(&out);
        StrAppendFmt(&output, "{c}", v);
    
        bool ok = (ZstrCompare(StrBegin(&output), "\\x1a\\xe0") == 0);
    
        StrDeinit(&output);
        Zstr b = "\x12";
        StrAppendFmt(&out, "{c}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x12") == 0);
    
        StrDeinit(&out);
        Zstr b = "\x90";
        StrAppendFmt(&out, "{c}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x90") == 0);
    
        StrDeinit(&out);
        Zstr b = "\xab";
        StrAppendFmt(&out, "{c}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xab") == 0);
    
        StrDeinit(&out);
        Zstr b = "\xcd";
        StrAppendFmt(&out, "{c}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xcd") == 0);
    
        StrDeinit(&out);
        Zstr b = "\xab";
        StrAppendFmt(&out, "{A}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xAB") == 0);
    
        StrDeinit(&out);
        Zstr b = "\xcd";
        StrAppendFmt(&out, "{A}", b);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xCD") == 0);
    
        StrDeinit(&out);
        Zstr lo_letter = "\x1b";
        StrAppendFmt(&out, "{c}", lo_letter);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\x1b") == 0);
        StrClear(&out);
        Zstr hi_letter = "\xb1";
        StrAppendFmt(&out, "{c}", hi_letter);
        ok = ok && (ZstrCompare(StrBegin(&out), "\\xb1") == 0);
    
        StrDeinit(&out);
        Zstr             p   = "\\n\\n#rest";
        StrReadFmt(p, "{}#", out);
        bool ok = (StrLen(&out) == 2) && (StrBegin(&out)[0] == '\n') && (StrBegin(&out)[1] == '\n');
        StrDeinit(&out);
        DefaultAllocatorDeinit(&a);
        StrReadFmt(in, "{}", f);
        Str  t  = FloatToStr(&f);
        bool ok = (ZstrCompare(StrBegin(&t), expect) == 0);
        StrDeinit(&t);
        FloatDeinit(&f);
        StrReadFmt(z, "{}", v);
        Str  t  = IntToStr(&v);
        bool ok = (ZstrCompare(StrBegin(&t), "12345") == 0);
        StrDeinit(&t);
        IntDeinit(&v);
        StrReadFmt(z, "{}", v);
        Str  t  = IntToStr(&v);
        bool ok = (ZstrCompare(StrBegin(&t), "99") == 0);
        StrDeinit(&t);
        IntDeinit(&v);
        StrReadFmt(z, "{x}", v);
        Str  t  = IntToStr(&v);
        bool ok = (ZstrCompare(StrBegin(&t), "255") == 0);
        StrDeinit(&t);
        IntDeinit(&v);
        // NULL; v unchanged (still 777).
        Str  t  = IntToStr(&v);
        bool ok = (out == NULL) && (ZstrCompare(StrBegin(&t), "777") == 0);
        StrDeinit(&t);
        IntDeinit(&v);
        StrReadFmt(z, "{}", f);
        Str  t  = FloatToStr(&f);
        bool ok = (ZstrCompare(StrBegin(&t), "3.14159") == 0);
        StrDeinit(&t);
        FloatDeinit(&f);
        Zstr out = str_read_fmt(z, "{}", (TypeSpecificIO[]) {TO_TYPE_SPECIFIC_IO(Float, &f)}, 1);
        Str  t   = FloatToStr(&f);
        bool ok  = (out == NULL) && (ZstrCompare(StrBegin(&t), "42") == 0);
        StrDeinit(&t);
        FloatDeinit(&f);
        Str s1 = StrInitFromZstr("Hello World", &alloc);
        StrReplace(&s1, "World", "Universe", 1);
        bool result = (ZstrCompare(StrBegin(&s1), "Hello Universe") == 0);
    
        // Test multiple replacements
        s1 = StrInitFromZstr("Hello Hello Hello", &alloc);
        StrReplace(&s1, "Hello", "Hi", 2);
        result = result && (ZstrCompare(StrBegin(&s1), "Hi Hi Hello") == 0);
    
        // Test Cstr-form (fixed-length views) - use the full "World" string instead of just "Wo"
        s1 = StrInitFromZstr("Hello World", &alloc);
        StrReplace(&s1, "World", 5, "Universe", 8, 1);
        result = result && (ZstrCompare(StrBegin(&s1), "Hello Universe") == 0);
    
        // Test Str-form
        Str replace = StrInitFromZstr("Universe", &alloc);
        StrReplace(&s1, &find, &replace, 1);
        result = result && (ZstrCompare(StrBegin(&s1), "Hello Universe") == 0);
    
        StrDeinit(&s1);
        bool result = (VecLen(&split) == 3);
        if (VecLen(&split) >= 3) {
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 0)), "Hello") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 1)), "World") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 2)), "Test") == 0);
        if (VecLen(&split) >= 3) {
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 0)), "Hello") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 1)), "World") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 2)), "Test") == 0);
        }
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 0)), "Hello") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 1)), "World") == 0);
            result = result && (ZstrCompare(StrBegin(VecPtrAt(&split, 2)), "Test") == 0);
        }
        Str  s1       = StrInitFromZstr("  Hello  ", &alloc);
        Str  stripped = StrLStrip(&s1, NULL);
        bool result   = (ZstrCompare(StrBegin(&stripped), "Hello  ") == 0);
        StrDeinit(&stripped);
        // Test StrRStrip
        stripped = StrRStrip(&s1, NULL);
        result   = result && (ZstrCompare(StrBegin(&stripped), "  Hello") == 0);
        StrDeinit(&stripped);
        // Test StrStrip
        stripped = StrStrip(&s1, NULL);
        result   = result && (ZstrCompare(StrBegin(&stripped), "Hello") == 0);
        StrDeinit(&stripped);
    
        stripped = StrLStrip(&s1, "*");
        result   = result && (ZstrCompare(StrBegin(&stripped), "Hello***") == 0);
        StrDeinit(&stripped);
    
        stripped = StrRStrip(&s1, "*");
        result   = result && (ZstrCompare(StrBegin(&stripped), "***Hello") == 0);
        StrDeinit(&stripped);
    
        stripped = StrStrip(&s1, "*");
        result   = result && (ZstrCompare(StrBegin(&stripped), "Hello") == 0);
        StrDeinit(&stripped);
        Str  s        = StrInitFromZstr("x", &alloc);
        Str  stripped = StrStrip(&s, "*");
        bool result   = (StrLen(&stripped) == 1) && (ZstrCompare(StrBegin(&stripped), "x") == 0);
    
        StrDeinit(&stripped);
        // Plant bytes beyond `a`'s logical length (still inside capacity 8) that
        // exceed the corresponding bytes of `b`. Only the mutant ever reads them.
        StrBegin(&a)[2] = (char)0xFF;
        StrBegin(&a)[3] = (char)0xFF;
        // exceed the corresponding bytes of `b`. Only the mutant ever reads them.
        StrBegin(&a)[2] = (char)0xFF;
        StrBegin(&a)[3] = (char)0xFF;
    
        Str b = StrInitFromZstr("abYY", &alloc); // length 4
    
        // Check that the characters were swapped
        bool result = (StrBegin(&s)[0] == 'o' && StrBegin(&s)[4] == 'H');
    
        // Swap 'e' and 'l'
    
        // Check that the characters were swapped
        result = result && (StrBegin(&s)[1] == 'l' && StrBegin(&s)[2] == 'e');
    
        StrDeinit(&s);
    
        // Length should now be 3 and content should be "Hel"
        result = result && (StrLen(&s) == 3) && (ZstrCompareN(StrBegin(&s), "Hel", 3) == 0);
    
        // Resize to a larger length
        // Length should now be 8, and the first 3 characters should still be "Hel"
        // The rest will be filled with zeros
        result = result && (StrLen(&s) == 8) && (ZstrCompareN(StrBegin(&s), "Hel", 3) == 0);
    
        StrDeinit(&s);
    
        // Data pointer should still be valid
        result = result && (StrBegin(&s) != NULL);
    
        StrDeinit(&s);
    
        // Check that the string was reversed
        bool result = (ZstrCompare(StrBegin(&s), "olleH") == 0);
    
        // Test with an even-length string
    
        // Check that the string was reversed
        result = result && (ZstrCompare(StrBegin(&s), "dcba") == 0);
    
        // Test with a single-character string
    
        // Check that the string is unchanged
        result = result && (ZstrCompare(StrBegin(&s), "a") == 0);
    
        // Test with an empty string
    
        // Check that it's initialized correctly
        bool result = (StrLen(&s) == len && ZstrCompareN(StrBegin(&s), test_str, len) == 0 && StrBegin(&s)[len] == '\0');
    
        StrDeinit(&s);
    
        // Check that it's initialized correctly
        bool result = (StrLen(&s) == ZstrLen(test_str) && ZstrCompare(StrBegin(&s), test_str) == 0);
    
        StrDeinit(&s);
        ValidateStr(&s);
    
        bool result = (StrLen(&s) == ZstrLen(test_str) && ZstrCompare(StrBegin(&s), test_str) == 0);
    
        StrDeinit(&s);
    
        // Check that dst is initialized correctly
        bool result = (StrLen(&dst) == StrLen(&src) && ZstrCompare(StrBegin(&dst), StrBegin(&src)) == 0);
    
        StrDeinit(&src);
    
        // Check that dst is initialized correctly
        bool result = (StrLen(&dst) == StrLen(&src) && ZstrCompare(StrBegin(&dst), StrBegin(&src)) == 0);
    
        StrDeinit(&src);
    
        // Check that it's initialized correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello, World!") == 0);
    
        StrDeinit(&s);
            ValidateStr(&stack_str);
    
            if (ZstrCompare(StrBegin(&stack_str), "Hello, Stack!") != 0) {
                result = false;
            }
    
        // Check that the copy was successful
        bool result = (success && StrLen(&dst) == StrLen(&src) && ZstrCompare(StrBegin(&dst), StrBegin(&src)) == 0);
    
        StrDeinit(&src);
    
        bool result = copied && StrLen(&dup) == StrLen(&src) && StrLen(&dst) == StrLen(&src) &&
                      ZstrCompare(StrBegin(&dup), StrBegin(&src)) == 0 &&
                      ZstrCompare(StrBegin(&dst), StrBegin(&src)) == 0 && dup_allocator_matches && dst_allocator_matches;
        bool result = copied && StrLen(&dup) == StrLen(&src) && StrLen(&dst) == StrLen(&src) &&
                      ZstrCompare(StrBegin(&dup), StrBegin(&src)) == 0 &&
                      ZstrCompare(StrBegin(&dst), StrBegin(&src)) == 0 && dup_allocator_matches && dst_allocator_matches;
    
        StrDeinit(&src);
    
        // Check that the character was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "He!llo") == 0);
    
        // Insert a character at the beginning
    
        // Check that the character was inserted correctly
        result = result && (ZstrCompare(StrBegin(&s), "?He!llo") == 0);
    
        // Insert a character at the end
    
        // Check that the character was inserted correctly
        result = result && (ZstrCompare(StrBegin(&s), "?He!llo.") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "He Worldllo") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "He Worldllo") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "He Worldllo") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "He Worldllo") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the string was inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the characters were inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the characters were inserted correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World") == 0);
    
        StrDeinit(&s);
    
        // Check that the strings were merged correctly
        bool result = (ZstrCompare(StrBegin(&s1), "Hello World") == 0);
    
        // Check that s2 was reset - data should be NULL, length should be 0
    
        // Check that s2 was reset - data should be NULL, length should be 0
        result = result && (StrLen(&s2) == 0 && StrBegin(&s2) == NULL);
    
        StrDeinit(&s1);
    
        // Check that the strings were merged correctly
        bool result = (ZstrCompare(StrBegin(&s1), "Hello World") == 0);
    
        // Check that s2 was not reset
    
        // Check that s2 was not reset
        result = result && (StrLen(&s2) == 6 && ZstrCompare(StrBegin(&s2), " World") == 0);
    
        StrDeinit(&s1);
    
        // Check that the strings were merged correctly
        bool result = (ZstrCompare(StrBegin(&s1), "Hello World") == 0);
    
        // s2 was zeroed on take per L-form contract
    
        // s2 was zeroed on take per L-form contract
        result = result && (StrLen(&s2) == 0 && StrBegin(&s2) == NULL);
    
        StrDeinit(&s1);
    
        // Check that the string was appended correctly
        bool result = (ZstrCompare(StrBegin(&s), "Hello World 2023") == 0);
    
        StrDeinit(&s);
        StrPushBackR(&s, 'o');
    
        bool result = (StrLen(&s) == 5 && ZstrCompare(StrBegin(&s), "Hello") == 0);
    
        StrDeinit(&s);
            Str *str2 = &VecAt(&sv, 1);
    
            result = result && (ZstrCompare(StrBegin(str1), "Hello") == 0);
            result = result && (ZstrCompare(StrBegin(str2), "World") == 0);
        }
    
            result = result && (ZstrCompare(StrBegin(str1), "Hello") == 0);
            result = result && (ZstrCompare(StrBegin(str2), "World") == 0);
        }
    
        // Check that the character was popped correctly
        bool result = (c == 'o' && ZstrCompare(StrBegin(&s), "Hell") == 0);
    
        // Pop another character without storing it - avoid passing NULL directly
    
        // Check that the character was removed
        result = result && (ZstrCompare(StrBegin(&s), "Hel") == 0);
    
        StrDeinit(&s);
    
        // Check that the character was popped correctly
        bool result = (c == 'H' && ZstrCompare(StrBegin(&s), "ello") == 0);
    
        // Pop another character without storing it - avoid passing NULL directly
    
        // Check that the character was removed
        result = result && (ZstrCompare(StrBegin(&s), "llo") == 0);
    
        StrDeinit(&s);
    
        // Check that the character was removed correctly
        bool result = (c == 'l' && ZstrCompare(StrBegin(&s), "Helo") == 0);
    
        // Remove another character without storing it - avoid passing NULL directly
    
        // Check that the character was removed
        result = result && (ZstrCompare(StrBegin(&s), "Hlo") == 0);
    
        StrDeinit(&s);
    
        // Check that the characters were removed correctly
        bool result = (ZstrCompare(buffer, " Worl") == 0 && ZstrCompare(StrBegin(&s), "Hellod") == 0);
    
        // Remove another range without storing it - use a temporary buffer instead of NULL
    
        // Check that the characters were removed
        result = result && (ZstrCompare(StrBegin(&s), "Hell") == 0);
    
        StrDeinit(&s);
    
        // Check that the character was deleted
        bool result = (ZstrCompare(StrBegin(&s), "Hell") == 0);
    
        // Delete another character
    
        // Check that the character was deleted
        result = result && (ZstrCompare(StrBegin(&s), "Hel") == 0);
    
        StrDeinit(&s);
    
        // Check that the character was deleted
        bool result = (ZstrCompare(StrBegin(&s), "Helo") == 0);
    
        // Delete another character
    
        // Check that the character was deleted
        result = result && (ZstrCompare(StrBegin(&s), "Hlo") == 0);
    
        StrDeinit(&s);
    
        // Check that the characters were deleted
        bool result = (ZstrCompare(StrBegin(&s), "Hello") == 0);
    
        // Delete another range
    
        // Check that the characters were deleted
        result = result && (ZstrCompare(StrBegin(&s), "Heo") == 0);
    
        StrDeinit(&s);
        StrIntFormat config = {.base = 10, .uppercase = false};
        StrFromU64(&s, 12345, &config);
        bool result = (ZstrCompare(StrBegin(&s), "12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '12345', got '{}'\n", s);
        config = (StrIntFormat) {.base = 16, .uppercase = false, .use_prefix = true};
        StrFromU64(&s, 0xABCD, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0xabcd") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0xabcd', got '{}'\n", s);
        config = (StrIntFormat) {.base = 16, .uppercase = true, .use_prefix = true};
        StrFromU64(&s, 0xABCD, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0xABCD") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0xABCD', got '{}'\n", s);
        config = (StrIntFormat) {.base = 2, .uppercase = false, .use_prefix = true};
        StrFromU64(&s, 42, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0b101010") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0b101010', got '{}'\n", s);
        config = (StrIntFormat) {.base = 8, .uppercase = false, .use_prefix = true};
        StrFromU64(&s, 42, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0o52") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0o52', got '{}'\n", s);
        config = (StrIntFormat) {.base = 10, .uppercase = false};
        StrFromU64(&s, 0, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0', got '{}'\n", s);
        StrIntFormat config = {.base = 10, .uppercase = false};
        StrFromI64(&s, 12345, &config);
        bool result = (ZstrCompare(StrBegin(&s), "12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '12345', got '{}'\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '12345', got '{}'\n", StrBegin(&s));
        }
        config = (StrIntFormat) {.base = 10, .uppercase = false};
        StrFromI64(&s, -12345, &config);
        result = result && (ZstrCompare(StrBegin(&s), "-12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '-12345', got '{}'\n", StrBegin(&s));
        result = result && (ZstrCompare(StrBegin(&s), "-12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '-12345', got '{}'\n", StrBegin(&s));
        }
        // For negative numbers in non-decimal bases, it uses unsigned representation
        // -0xABCD = -(43981) = large positive number when treated as unsigned
        result = result && (ZstrCompareN(StrBegin(&s), "0x", 2) == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected hex prefix '0x', got '{}'\n", StrBegin(&s));
        result = result && (ZstrCompareN(StrBegin(&s), "0x", 2) == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected hex prefix '0x', got '{}'\n", StrBegin(&s));
        }
        config = (StrIntFormat) {.base = 10, .uppercase = false};
        StrFromI64(&s, 0, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0', got '{}'\n", StrBegin(&s));
        result = result && (ZstrCompare(StrBegin(&s), "0") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0', got '{}'\n", StrBegin(&s));
        }
        config = (StrIntFormat) {.base = 2, .uppercase = false, .use_prefix = true};
        StrFromI64(&s, 42, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0b101010") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0b101010', got '{}'\n", StrBegin(&s));
        result = result && (ZstrCompare(StrBegin(&s), "0b101010") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '0b101010', got '{}'\n", StrBegin(&s));
        }
        StrFloatFormat config = {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 123.0, &config);
        bool result = (ZstrCompare(StrBegin(&s), "123.00") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '123.00', got '{}'\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "123.00") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '123.00', got '{}'\n", StrBegin(&s));
        }
        config = (StrFloatFormat) {.precision = 3, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 123.456, &config);
        result = result && (ZstrCompare(StrBegin(&s), "123.456") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '123.456', got '{}'\n", StrBegin(&s));
        result = result && (ZstrCompare(StrBegin(&s), "123.456") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '123.456', got '{}'\n", StrBegin(&s));
        }
        config = (StrFloatFormat) {.precision = 3, .force_sci = false, .uppercase = false};
        StrFromF64(&s, -123.456, &config);
        result = result && (ZstrCompare(StrBegin(&s), "-123.456") == 0);
    
        // Test scientific notation (forced)
        config = (StrFloatFormat) {.precision = 3, .force_sci = true, .uppercase = false};
        StrFromF64(&s, 123.456, &config);
        result = result && (ZstrCompare(StrBegin(&s), "1.235e+02") == 0);
    
        // Test scientific notation (uppercase)
        config = (StrFloatFormat) {.precision = 3, .force_sci = true, .uppercase = true};
        StrFromF64(&s, 123.456, &config);
        result = result && (ZstrCompare(StrBegin(&s), "1.235E+02") == 0);
    
        // Test very small number (auto scientific notation)
        config = (StrFloatFormat) {.precision = 3, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 0.0000123, &config);
        result = result && (ZstrCompare(StrBegin(&s), "1.230e-05") == 0);
    
        // Test very large number (auto scientific notation)
        config = (StrFloatFormat) {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 1234567890123.0, &config);
        result = result && (ZstrCompare(StrBegin(&s), "1.23e+12") == 0);
    
        // Test zero
        config = (StrFloatFormat) {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 0.0, &config);
        result = result && (ZstrCompare(StrBegin(&s), "0.00") == 0);
    
        // Test infinity
        config = (StrFloatFormat) {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, F64_INFINITY, &config);
        result = result && (ZstrCompare(StrBegin(&s), "inf") == 0);
    
        // Test negative infinity
        config = (StrFloatFormat) {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, -F64_INFINITY, &config);
        result = result && (ZstrCompare(StrBegin(&s), "-inf") == 0);
    
        // Test NaN
        config = (StrFloatFormat) {.precision = 2, .force_sci = false, .uppercase = false};
        StrFromF64(&s, F64_NAN, &config);
        result = result && (ZstrCompare(StrBegin(&s), "nan") == 0);
    
        StrDeinit(&s);
    
            // String should have expected decimal places
            Zstr dot_pos = ZstrFindChar(StrBegin(&s), '.');
            if (dot_pos) {
                size decimal_places = ZstrLen(dot_pos + 1);
            StrFloatFormat config = {.precision = 3, .force_sci = true, .uppercase = false};
            StrFromF64(&s, sci_values[i], &config);
            bool has_e = (ZstrFindChar(StrBegin(&s), 'e') != NULL);
            result     = result && has_e;
            config = (StrFloatFormat) {.precision = 3, .force_sci = true, .uppercase = true};
            StrFromF64(&s, sci_values[i], &config);
            bool has_E = (ZstrFindChar(StrBegin(&s), 'E') != NULL);
            result     = result && has_E;
        bool ok = true;
        StrInitStack(view, 8) {
            char *d     = StrBegin(&view);
            d[0]        = ' ';
            d[1]        = 'n';
        bool ok = true;
        StrInitStack(view, 8) {
            char *d     = StrBegin(&view);
            d[0]        = '-';
            d[1]        = 'i';
        StrFromF64(&s, F64_NAN, &config);
    
        bool result = (StrLen(&s) == 3) && (ZstrCompare(StrBegin(&s), "nan") == 0);
        if (!result)
            WriteFmt("    FAIL: expected len 3 \"nan\", got len {} \"{}\"\n", StrLen(&s), StrBegin(&s));
        bool result = (StrLen(&s) == 3) && (ZstrCompare(StrBegin(&s), "nan") == 0);
        if (!result)
            WriteFmt("    FAIL: expected len 3 \"nan\", got len {} \"{}\"\n", StrLen(&s), StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, F64_INFINITY, &config);
    
        bool result = (StrLen(&s) == 3) && (ZstrCompare(StrBegin(&s), "inf") == 0);
        if (!result)
            WriteFmt("    FAIL: expected len 3 \"inf\", got len {} \"{}\"\n", StrLen(&s), StrBegin(&s));
        bool result = (StrLen(&s) == 3) && (ZstrCompare(StrBegin(&s), "inf") == 0);
        if (!result)
            WriteFmt("    FAIL: expected len 3 \"inf\", got len {} \"{}\"\n", StrLen(&s), StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 0.0001, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "0.000100") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"0.000100\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "0.000100") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"0.000100\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 1e7, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "1.00e+07") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"1.00e+07\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "1.00e+07") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"1.00e+07\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 5.0, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "5e+00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"5e+00\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "5e+00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"5e+00\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 5.0, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "5.00e+00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"5.00e+00\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "5.00e+00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"5.00e+00\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        Str           *r      = StrFromF64(&s, 123.456, &config);
    
        bool result = (r == &s) && (ZstrCompare(StrBegin(&s), "1.23e+02") == 0);
        if (!result)
            WriteFmt("    FAIL: expected handle + \"1.23e+02\", got null={} \"{}\"\n", (r == NULL), StrBegin(&s));
        bool result = (r == &s) && (ZstrCompare(StrBegin(&s), "1.23e+02") == 0);
        if (!result)
            WriteFmt("    FAIL: expected handle + \"1.23e+02\", got null={} \"{}\"\n", (r == NULL), StrBegin(&s));
    
        StrDeinit(&s);
        Str           *r      = StrFromF64(&s, 123.0, &config);
    
        bool result = (r == &s) && (ZstrCompare(StrBegin(&s), "123.00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected handle + \"123.00\", got null={} \"{}\"\n", (r == NULL), StrBegin(&s));
        bool result = (r == &s) && (ZstrCompare(StrBegin(&s), "123.00") == 0);
        if (!result)
            WriteFmt("    FAIL: expected handle + \"123.00\", got null={} \"{}\"\n", (r == NULL), StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 123.0, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "123") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"123\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "123") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"123\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 123.456, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "123.456") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"123.456\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "123.456") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"123.456\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrFromF64(&s, 0.1235, &config);
    
        bool result = (ZstrCompare(StrBegin(&s), "0.124") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"0.124\", got \"{}\"\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "0.124") == 0);
        if (!result)
            WriteFmt("    FAIL: expected \"0.124\", got \"{}\"\n", StrBegin(&s));
    
        StrDeinit(&s);
        StrIntFormat config = {.base = 10, .uppercase = false};
        StrFromI64(&s, INT64_MIN, &config);
        bool result = (ZstrCompare(StrBegin(&s), "-9223372036854775808") == 0);
    
        StrDeinit(&s);
        StrFloatFormat config = {.precision = 1, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 2.25, &config);
        bool result = (ZstrCompare(StrBegin(&s), "2.3") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '2.3', got '{}'\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "2.3") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '2.3', got '{}'\n", StrBegin(&s));
        }
        StrFloatFormat config = {.precision = 1, .force_sci = false, .uppercase = false};
        StrFromF64(&s, 2.25, &config);
        bool result = (ZstrCompare(StrBegin(&s), "2.3") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '2.3', got '{}'\n", StrBegin(&s));
        bool result = (ZstrCompare(StrBegin(&s), "2.3") == 0);
        if (!result) {
            WriteFmt("    FAIL: Expected '2.3', got '{}'\n", StrBegin(&s));
        }
        Str         *ret    = StrFromU64(&s, 12345, &config);
    
        bool result = (ret == &s) && (ZstrCompare(StrBegin(&s), "12345") == 0);
        if (!result) {
            WriteFmt("    FAIL: expected &s and '12345', got ret={} '{}'\n", (ret != NULL), s);
    
        // The result should be "H0e1l2l3o4"
        bool success = (ZstrCompare(StrBegin(&result), "H0e1l2l3o4") == 0);
    
        StrDeinit(&s);
        }
    
        bool success = (ZstrCompare(StrBegin(&result), "o4l3l2e1H0") == 0);
        WriteFmt("  (Index 0 was processed)\n");
    
        // The result should be "H0e1l2l3o4"
        bool success = (ZstrCompare(StrBegin(&result), "H0e1l2l3o4") == 0);
    
        // The original string should now be "HELLO" (all uppercase)
    
        // The original string should now be "HELLO" (all uppercase)
        success = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0);
    
        StrDeinit(&s);
    
        bool success = false;
        success      = (ZstrCompare(StrBegin(&result), "o4l3l2e1H0") == 0);
        success      = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0); // All uppercase
        WriteFmt("  (Index 0 was processed)\n");
        bool success = false;
        success      = (ZstrCompare(StrBegin(&result), "o4l3l2e1H0") == 0);
        success      = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0); // All uppercase
        WriteFmt("  (Index 0 was processed)\n");
    
        // The result should be "Hello"
        bool success = (ZstrCompare(StrBegin(&result), "Hello") == 0);
    
        StrDeinit(&s);
        bool success = false;
        if (char_count == StrLen(&s)) {
            success = (ZstrCompare(StrBegin(&result), "olleH") == 0);
            WriteFmt("  (All characters were processed)\n");
        } else {
            WriteFmt("  (All characters were processed)\n");
        } else {
            success = (ZstrCompare(StrBegin(&result), "olle") == 0);
            WriteFmt("  (First character was NOT processed - bug in macro)\n");
        }
    
        // The result should be "Hello" (original values before modification)
        bool success = (ZstrCompare(StrBegin(&result), "Hello") == 0);
    
        // The original string should now be "HELLO" (all uppercase)
    
        // The original string should now be "HELLO" (all uppercase)
        success = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0);
    
        StrDeinit(&s);
        bool success = false;
        if (char_count == StrLen(&s)) {
            success = (ZstrCompare(StrBegin(&result), "olleH") == 0);
            success = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0); // All uppercase
            WriteFmt("  (All characters were processed)\n");
        if (char_count == StrLen(&s)) {
            success = (ZstrCompare(StrBegin(&result), "olleH") == 0);
            success = success && (ZstrCompare(StrBegin(&s), "HELLO") == 0); // All uppercase
            WriteFmt("  (All characters were processed)\n");
        } else {
            WriteFmt("  (All characters were processed)\n");
        } else {
            success = (ZstrCompare(StrBegin(&result), "olle") == 0);
            success = success && (ZstrCompare(StrBegin(&s), "HELLo") == 0); // All uppercase except first char
            WriteFmt("  (First character was NOT processed - bug in macro)\n");
        } else {
            success = (ZstrCompare(StrBegin(&result), "olle") == 0);
            success = success && (ZstrCompare(StrBegin(&s), "HELLo") == 0); // All uppercase except first char
            WriteFmt("  (First character was NOT processed - bug in macro)\n");
        }
    
        // The result should be "W6o7r8l9d10" (characters from index 6-10 with their indices)
        bool success = (ZstrCompare(StrBegin(&result), "W6o7r8l9d10") == 0);
    
        // Test with empty range
    
        // The result should be "Hello" (first 5 characters)
        bool success = (ZstrCompare(StrBegin(&result), "Hello") == 0);
    
        // Test with range at the end of the string
    
        // The end_result should be "World" (last 5 characters)
        success = success && (ZstrCompare(StrBegin(&end_result), "World") == 0);
    
        StrDeinit(&s);
    
        // The result should be "W6o7r8l9d10" (characters from index 6-10 with their indices)
        bool success = (ZstrCompare(StrBegin(&result), "W6o7r8l9d10") == 0);
    
        // The original string should now have "WORLD" in uppercase
    
        // The original string should now have "WORLD" in uppercase
        success = success && (ZstrCompare(StrBegin(&s), "Hello WORLD") == 0);
    
        StrDeinit(&s);
    
        // The result should be "Hello" (first 5 characters)
        bool success = (ZstrCompare(StrBegin(&result), "Hello") == 0);
    
        // The original string should now have "HELLO" in uppercase
    
        // The original string should now have "HELLO" in uppercase
        success = success && (ZstrCompare(StrBegin(&s), "HELLO World") == 0);
    
        StrDeinit(&s);
    // Test StrBegin function
    bool test_str_begin(void) {
        WriteFmt("Testing StrBegin\n");
        DefaultAllocator alloc = DefaultAllocatorInit();
    
        // Get a pointer to the first character using StrBegin
        char *begin = StrBegin(&s);
    
        // Check that the pointer dereferences to the expected first character.
        // (Apple's C mangling prepends `_`; substring search matches both
        // "bt_capture_with_helper" and "_bt_capture_with_helper".)
        bool ok = StrLen(&rendered) > 0 && ZstrFindSubstring(StrBegin(&rendered), "bt_capture_with_helper") != NULL &&
                  ZstrFindSubstring(StrBegin(&rendered), "bt_capture_outer") != NULL;
        // "bt_capture_with_helper" and "_bt_capture_with_helper".)
        bool ok = StrLen(&rendered) > 0 && ZstrFindSubstring(StrBegin(&rendered), "bt_capture_with_helper") != NULL &&
                  ZstrFindSubstring(StrBegin(&rendered), "bt_capture_outer") != NULL;
    
    #if FEATURE_SYS_SYMRESOLVE
        // the Linux backend emits source filenames today (via DwarfLines);
        // macOS / Windows only emit names + offsets.
        ok = ok && ZstrFindSubstring(StrBegin(&rendered), "Backtrace.c") != NULL;
    #endif
    
        ok = ok && StrLen(&rendered) > 0;
        ok = ok && ZstrFindSubstring(StrBegin(&rendered), "bt_vec_capture_with_helper") != NULL;
        ok = ok && ZstrFindSubstring(StrBegin(&rendered), "bt_vec_capture_outer") != NULL;
        ok = ok && StrLen(&rendered) > 0;
        ok = ok && ZstrFindSubstring(StrBegin(&rendered), "bt_vec_capture_with_helper") != NULL;
        ok = ok && ZstrFindSubstring(StrBegin(&rendered), "bt_vec_capture_outer") != NULL;
    
        StrDeinit(&rendered);
    
        // Should also contain the helper name through the shared resolver.
        bool ok = StrLen(&out) > 0 && ZstrFindSubstring(StrBegin(&out), "bt_capture_with_helper") != NULL;
    
        StrDeinit(&out);
        bool ok = n >= 2;
        ok      = ok && StrLen(&rendered) > 0;
        ok      = ok && ZstrFindSubstring(StrBegin(&rendered), "cfi_capture_inner") != NULL;
        ok      = ok && ZstrFindSubstring(StrBegin(&rendered), "cfi_capture_outer") != NULL;
        ok      = ok && StrLen(&rendered) > 0;
        ok      = ok && ZstrFindSubstring(StrBegin(&rendered), "cfi_capture_inner") != NULL;
        ok      = ok && ZstrFindSubstring(StrBegin(&rendered), "cfi_capture_outer") != NULL;
    
        StrDeinit(&rendered);
        }
        Str  s  = SocketAddrFormat(ad, a);
        bool ok = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), expect) == 0;
        StrDeinit(&s);
        return ok;
        }
        Str  s  = SocketAddrFormat(ad, a);
        bool ok = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), expect) == 0;
        StrDeinit(&s);
        return ok;
    static const HostsEntry *find_host(HostsTable *t, Zstr name) {
        VecForeachPtr(t, e) {
            if (StrLen(&e->name) > 0 && ZstrCompare(StrBegin(&e->name), name) == 0) {
                return e;
            }
        }
        Str  s  = SocketAddrFormat(VecPtrAt(&r->nameservers, i), a);
        bool ok = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), expect) == 0;
        StrDeinit(&s);
        return ok;
        if (ok) {
            Str s = SocketAddrFormat(VecPtrAt(&out, 0), a);
            ok    = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), "203.0.113.7:9999") == 0;
            StrDeinit(&s);
        }
        if (ok) {
            Str s = SocketAddrFormat(VecPtrAt(&out, 0), a);
            ok    = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), "[::1]:443") == 0;
            StrDeinit(&s);
        }
                Str s = SocketAddrFormat(ad, a);
                u64 L = StrLen(&s);
                if (L < 3 || StrBegin(&s)[L - 1] != '3' || StrBegin(&s)[L - 2] != '5' || StrBegin(&s)[L - 3] != ':') {
                    ok = false;
                }
        if (ok) {
            Str s = SocketAddrFormat(&one, a);
            ok    = (StrLen(&s) > 0) && ZstrCompare(StrBegin(&s), "127.0.0.1:80") == 0;
            StrDeinit(&s);
        }
    
        const HostsEntry *e = find_host(&r.hosts, "localhost");
        bool ok = VecLen(&r.hosts) == 1 && host_v4_is(e, 127, 0, 0, 1) && ZstrCompare(StrBegin(&e->name), "localhost") == 0;
    
        drop_temp(&path);
    
        const HostsEntry *e = find_host(&r.hosts, "namex");
        bool ok = VecLen(&r.hosts) == 1 && host_v4_is(e, 10, 0, 0, 2) && ZstrCompare(StrBegin(&e->name), "namex") == 0;
    
        drop_temp(&path);
    
        const HostsEntry *e = find_host(&r.hosts, "@az[`m");
        bool ok = VecLen(&r.hosts) == 1 && host_v4_is(e, 10, 1, 1, 2) && ZstrCompare(StrBegin(&e->name), "@az[`m") == 0;
    
        drop_temp(&path);
        DnsResolver r;
        resolver_init_empty(&r, a);
        Str path = write_temp(a, StrBegin(&body));
        DnsResolverAddHostsPath(&r, &path);
        StrPushBackMany(&smeared, "ZZZ", 3);
    
        bool added = DnsResolverAddHostsPath(&r, StrBegin(&smeared), plen);
    
        bool ok = added && VecLen(&r.hosts) == 1 && host_v4_is(find_host(&r.hosts, "lenhost"), 1, 2, 3, 4);
        DnsResolver r;
        resolver_init_empty(&r, a);
        DnsResolverAddHostsPath(&r, StrBegin(&path), plen);
        DnsResolverDeinit(&r);
            "nameserver 8.8.8.8\n"
        );
        bool added = DnsResolverAddPath(&r, StrBegin(&path), StrLen(&path));
    
        bool ok = added && VecLen(&r.hosts) == 1 && host_v4_is(find_host(&r.hosts, "zlhost"), 1, 2, 3, 4) &&
        resolver_init_empty(&r, a);
        Str  path  = write_temp(a, "nameserver 4.3.2.1\n");
        bool added = DnsResolverAddResolvPath(&r, StrBegin(&path), StrLen(&path));
    
        bool ok = added && VecLen(&r.nameservers) == 1 && ns_fmt_is(&r, 0, a, "4.3.2.1:53") && VecLen(&r.hosts) == 0;
        Str        local_str = SocketAddrFormat(&local, a);
        SocketAddr connect_addr;
        bool       parsed = SocketAddrParse(&connect_addr, (Zstr)StrBegin(&local_str), SOCKET_KIND_TCP);
        StrDeinit(&local_str);
        if (!parsed) {
            }
            Str rendered = SocketAddrFormat(&addr, alloc_base);
            ok           = ok && StrLen(&rendered) > 0 && ZstrCompare(StrBegin(&rendered), "127.0.0.1:8080") == 0;
            StrDeinit(&rendered);
        }
            }
            Str rendered = SocketAddrFormat(&addr, alloc_base);
            ok           = ok && StrLen(&rendered) > 0 && ZstrCompare(StrBegin(&rendered), "[::1]:8080") == 0;
            StrDeinit(&rendered);
        }
        Str        local_str = SocketAddrFormat(&local, a);
        SocketAddr connect_addr;
        bool       parsed = SocketAddrParse(&connect_addr, (Zstr)StrBegin(&local_str), SOCKET_KIND_TCP);
        StrDeinit(&local_str);
        if (!parsed) {
        if (ok) {
            Str r = SocketAddrFormat(&addr, a);
            ok    = StrLen(&r) > 0 && ZstrCompare(StrBegin(&r), expect) == 0;
            StrDeinit(&r);
        }
    
        Str s = SocketAddrFormat(&addr, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompare(StrBegin(&s), "1.2.3.4:80") == 0;
        StrDeinit(&s);
    
        Str s = SocketAddrFormat(&addr, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompare(StrBegin(&s), "10.0.0.1:4660") == 0;
        StrDeinit(&s);
    
        Str s = SocketAddrFormat(&addr, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompare(StrBegin(&s), "[2001:db8::1]:443") == 0;
        StrDeinit(&s);
    
        Str s = SocketAddrFormat(&addr, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompare(StrBegin(&s), "[::1]:8080") == 0;
        StrDeinit(&s);
    
        Str s = SocketAddrFormat(&local, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompare(StrBegin(&s), "127.0.0.1:4660") == 0;
        StrDeinit(&s);
        ok    = ok && StrLen(&s) > 0;
        if (ok) {
            Zstr rendered = StrBegin(&s);
            ok            = ok && ZstrCompareN(rendered, "127.0.0.1:", 10u) == 0;
            // a real ephemeral port is non-zero: last char is not ":0\0"
        Str        local_str = SocketAddrFormat(&local, a);
        SocketAddr connect_addr;
        bool       parsed = SocketAddrParse(&connect_addr, (Zstr)StrBegin(&local_str), SOCKET_KIND_TCP);
        StrDeinit(&local_str);
        if (!parsed) {
        Str        local_str = SocketAddrFormat(&local, a);
        SocketAddr connect_addr;
        bool       parsed = SocketAddrParse(&connect_addr, (Zstr)StrBegin(&local_str), SOCKET_KIND_TCP);
        StrDeinit(&local_str);
        if (!parsed) {
        {
            Str  peer = SocketAddrFormat(&server.peer, a);
            Zstr p    = StrBegin(&peer);
            ok        = ok && StrLen(&peer) > 0 && p[0] == '1' && p[1] == '2' && p[2] == '7' && p[3] == '.';
            StrDeinit(&peer);
        // must start with the loopback host and a colon, then a non-"0" port.
        ok = ok && local.family == SOCKET_FAMILY_INET;
        ok = ok && ZstrCompare(StrBegin(&rendered), "127.0.0.1:0") != 0;
        // host portion must be exactly the loopback address.
        Zstr r = StrBegin(&rendered);
        ok = ok && ZstrCompare(StrBegin(&rendered), "127.0.0.1:0") != 0;
        // host portion must be exactly the loopback address.
        Zstr r = StrBegin(&rendered);
        ok     = ok && r[0] == '1' && r[1] == '2' && r[2] == '7' && r[3] == '.';
        StrDeinit(&rendered);
            if (p) {
                Str r = SocketAddrFormat(&addr, a);
                ok    = ok && ZstrCompare(StrBegin(&r), "127.0.0.1:65535") == 0;
                StrDeinit(&r);
            }
            if (p) {
                Str r = SocketAddrFormat(&addr, a);
                ok    = ok && ZstrCompare(StrBegin(&r), "127.0.0.1:0") == 0;
                StrDeinit(&r);
            }
            if (p) {
                Str r = SocketAddrFormat(&addr, a);
                ok    = ok && ZstrCompare(StrBegin(&r), "1.2.3.4:4660") == 0;
                StrDeinit(&r);
            }
        if (p) {
            Str r = SocketAddrFormat(&addr, a);
            ok    = ok && ZstrCompare(StrBegin(&r), "1.2.3.4:4660") == 0;
            StrDeinit(&r);
        }
            if (p) {
                Str r = SocketAddrFormat(&addr, a);
                ok    = ok && ZstrCompare(StrBegin(&r), "[::1]:4660") == 0;
                StrDeinit(&r);
            }
        if (ok) {
            Str r = SocketAddrFormat(&addr, a);
            ok    = StrLen(&r) > 0 && ZstrCompare(StrBegin(&r), expect) == 0;
            StrDeinit(&r);
        }
    
        Str s = SocketAddrFormat(&local, a);
        ok    = ok && StrLen(&s) > 0 && ZstrCompareN(StrBegin(&s), "127.0.0.1:", 10u) == 0;
        StrDeinit(&s);
        }
        FileClose(&f);
        if (FileWriteAndClose((Zstr)StrBegin(&path), blob, sizeof(blob)) < 0) {
            FileRemove(&path);
            StrDeinit(&path);
    
        Pe   pe;
        bool ok = PeOpen(&pe, (Zstr)StrBegin(&path), base);
        if (ok) {
            ok = pe.machine == PE_MACHINE_X86_64 && VecLen(&pe.sections) == 1 &&
        }
        FileClose(&f);
        if (FileWriteAndClose((Zstr)StrBegin(&path), junk, sizeof(junk)) < 0) {
            FileRemove(&path);
            StrDeinit(&path);
    
        Pe   pe;
        bool opened = PeOpen(&pe, (Zstr)StrBegin(&path), base);
        if (opened)
            PeDeinit(&pe);
            DnsRecord *r0 = VecPtrAt(&resp.answers, 0);
            match         = r0->type == DNS_TYPE_A && r0->ttl == 300 && r0->ipv4[0] == 93 && r0->ipv4[1] == 184 &&
                    r0->ipv4[2] == 216 && r0->ipv4[3] == 34 && ZstrCompare(StrBegin(&r0->name), "example.com") == 0;
        }
        if (match) {
        if (match) {
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = r->type == DNS_TYPE_CNAME && ZstrCompare(StrBegin(&r->target), "example.com") == 0;
        }
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = r->type == DNS_TYPE_A && r->ttl == 300 && r->ipv4[0] == 0x0a && r->ipv4[1] == 0x0b &&
                    r->ipv4[2] == 0x0c && r->ipv4[3] == 0x0d && ZstrCompare(StrBegin(&r->name), "www.example.com") == 0;
        }
        if (match) {
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = r->type == DNS_TYPE_A && ZstrCompare(StrBegin(&r->name), "zz") == 0;
        }
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match =
                r->type == DNS_TYPE_A && r->ttl == 2 && ZstrCompare(StrBegin(&r->name), "abc.de") == 0 && r->ipv4[0] == 9;
        }
            match        = r->type == DNS_TYPE_A && r->rclass == 1 && r->ttl == 0x01020304u && r->ipv4[0] == 8 &&
                    r->ipv4[1] == 8 && r->ipv4[2] == 4 && r->ipv4[3] == 4 && r->ipv6[0] == 0 &&
                    ZstrCompare(StrBegin(&r->name), "a") == 0;
            // rdata raw stash must equal the 4 IP bytes.
            match = match && BufLength(&r->rdata) == 4 && BufData(&r->rdata)[0] == 8 && BufData(&r->rdata)[1] == 8 &&
            DnsRecord *r0 = VecPtrAt(&resp.answers, 0);
            DnsRecord *r1 = VecPtrAt(&resp.answers, 1);
            match = ZstrCompare(StrBegin(&r0->name), "x") == 0 && r0->ttl == 1 && r0->ipv4[0] == 1 && r0->ipv4[3] == 4 &&
                    ZstrCompare(StrBegin(&r1->name), "y") == 0 && r1->ttl == 2 && r1->ipv4[0] == 5 && r1->ipv4[3] == 8;
        }
            DnsRecord *r1 = VecPtrAt(&resp.answers, 1);
            match = ZstrCompare(StrBegin(&r0->name), "x") == 0 && r0->ttl == 1 && r0->ipv4[0] == 1 && r0->ipv4[3] == 4 &&
                    ZstrCompare(StrBegin(&r1->name), "y") == 0 && r1->ttl == 2 && r1->ipv4[0] == 5 && r1->ipv4[3] == 8;
        }
            DnsRecord *ns = VecPtrAt(&resp.authority, 0);
            DnsRecord *ar = VecPtrAt(&resp.additional, 0);
            match         = ZstrCompare(StrBegin(&an->name), "an") == 0 && an->ipv4[0] == 11 &&
                    ZstrCompare(StrBegin(&ns->name), "ns") == 0 && ns->ipv4[0] == 22 &&
                    ZstrCompare(StrBegin(&ar->name), "ad") == 0 && ar->ipv4[0] == 33;
            DnsRecord *ar = VecPtrAt(&resp.additional, 0);
            match         = ZstrCompare(StrBegin(&an->name), "an") == 0 && an->ipv4[0] == 11 &&
                    ZstrCompare(StrBegin(&ns->name), "ns") == 0 && ns->ipv4[0] == 22 &&
                    ZstrCompare(StrBegin(&ar->name), "ad") == 0 && ar->ipv4[0] == 33;
        }
            match         = ZstrCompare(StrBegin(&an->name), "an") == 0 && an->ipv4[0] == 11 &&
                    ZstrCompare(StrBegin(&ns->name), "ns") == 0 && ns->ipv4[0] == 22 &&
                    ZstrCompare(StrBegin(&ar->name), "ad") == 0 && ar->ipv4[0] == 33;
        }
        if (match) {
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = ZstrCompare(StrBegin(&r->name), "q") == 0 && r->ipv4[0] == 9 && r->ttl == 5;
        }
        if (match) {
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = r->type == DNS_TYPE_CNAME && ZstrCompare(StrBegin(&r->target), "to") == 0;
        }
        if (match) {
            DnsRecord *r = VecPtrAt(&resp.answers, 0);
            match        = r->type == DNS_TYPE_A && r->ttl == 7 && ZstrCompare(StrBegin(&r->name), "zz") == 0;
        }
    
        bool ok = (next != raw) && (req.method == HTTP_REQUEST_METHOD_GET) && (StrLen(&req.url) == 11) &&
                  (ZstrCompare(StrBegin(&req.url), "/index.html") == 0) && (VecLen(&req.headers) == 2) &&
                  (ZstrCompare(next, "body-bytes") == 0);
    
        HttpHeader *host = HttpHeadersFind(&req.headers, "Host");
        ok               = ok && host && ZstrCompare(StrBegin(&host->value), "example.com") == 0;
    
        HttpRequestDeinit(&req);
        //   - includes a Content-Length: 11 (length of "<h1>hi</h1>")
        //   - ends with the body
        bool ok = StrLen(&wire) > 0 && ZstrFindSubstring(StrBegin(&wire), "HTTP/1.1 200 OK\r\n") == StrBegin(&wire) &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Type: text/html\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Length: 11\r\n") != NULL &&
        //   - ends with the body
        bool ok = StrLen(&wire) > 0 && ZstrFindSubstring(StrBegin(&wire), "HTTP/1.1 200 OK\r\n") == StrBegin(&wire) &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Type: text/html\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Length: 11\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "\r\n\r\n<h1>hi</h1>") != NULL;
        bool ok = StrLen(&wire) > 0 && ZstrFindSubstring(StrBegin(&wire), "HTTP/1.1 200 OK\r\n") == StrBegin(&wire) &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Type: text/html\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Length: 11\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "\r\n\r\n<h1>hi</h1>") != NULL;
                  ZstrFindSubstring(StrBegin(&wire), "Content-Type: text/html\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "Content-Length: 11\r\n") != NULL &&
                  ZstrFindSubstring(StrBegin(&wire), "\r\n\r\n<h1>hi</h1>") != NULL;
    
        StrDeinit(&wire);
    
        HttpRequest req  = HttpRequestInit(alloc_base);
        Zstr        in   = StrBegin(&raw);
        Zstr        next = HttpRequestParse(&req, in);
    
        HttpRequest req  = HttpRequestInit(alloc_base);
        Zstr        in   = StrBegin(&raw);
        Zstr        next = HttpRequestParse(&req, in);
        HttpResponse  response = HttpResponseInit(alloc_base);
        HttpResponse *res =
            HttpRespondWithFile(&response, HTTP_RESPONSE_CODE_OK, HTTP_CONTENT_TYPE_TEXT_PLAIN, StrBegin(&path));
    
        ok = ok && (res != NULL) && (response.status_code == HTTP_RESPONSE_CODE_OK) &&
        ok = ok && (res != NULL) && (response.status_code == HTTP_RESPONSE_CODE_OK) &&
             (response.content_type == HTTP_CONTENT_TYPE_TEXT_PLAIN) && (StrLen(&response.body) == ZstrLen(payload)) &&
             (ZstrCompare(StrBegin(&response.body), payload) == 0);
    
        FileRemove(StrBegin(&path));
             (ZstrCompare(StrBegin(&response.body), payload) == 0);
    
        FileRemove(StrBegin(&path));
        StrDeinit(&path);
        HttpResponseDeinit(&response);
        HttpResponse  response = HttpResponseInit(alloc_base);
        HttpResponse *res =
            HttpRespondWithFile(&response, HTTP_RESPONSE_CODE_OK, HTTP_CONTENT_TYPE_TEXT_PLAIN, StrBegin(&path));
    
        ok = ok && (res != NULL) && (response.status_code == HTTP_RESPONSE_CODE_OK) && (StrLen(&response.body) == 0);
        ok = ok && (res != NULL) && (response.status_code == HTTP_RESPONSE_CODE_OK) && (StrLen(&response.body) == 0);
    
        FileRemove(StrBegin(&path));
        StrDeinit(&path);
        HttpResponseDeinit(&response);
        // Serving the file must free the old (HTML) body before installing the new.
        HttpResponse *res =
            HttpRespondWithFile(&response, HTTP_RESPONSE_CODE_OK, HTTP_CONTENT_TYPE_TEXT_PLAIN, StrBegin(&path));
        ok = ok && (res != NULL);
        ok = ok && (res != NULL);
    
        FileRemove(StrBegin(&path));
        StrDeinit(&path);
        HttpResponseDeinit(&response);
            WriteFmt("[DEBUG] Name check failed: expected 'Alice', got '");
            for (size i = 0; i < StrLen(&name); i++) {
                WriteFmt("{c}", StrBegin(&name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] City check failed: expected 'New York', got '");
            for (size i = 0; i < StrLen(&city); i++) {
                WriteFmt("{c}", StrBegin(&city)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Person name check failed: expected 'Bob', got '");
            for (size i = 0; i < StrLen(&person.name); i++) {
                WriteFmt("{c}", StrBegin(&person.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Log level check failed: expected 'INFO', got '");
            for (size i = 0; i < StrLen(&config.log_level); i++) {
                WriteFmt("{c}", StrBegin(&config.log_level)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Language 1 check failed: expected 'C', got '");
                for (size i = 0; i < StrLen(lang1); i++) {
                    WriteFmt("{c}", StrBegin(lang1)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Language 2 check failed: expected 'Python', got '");
                for (size i = 0; i < StrLen(lang2); i++) {
                    WriteFmt("{c}", StrBegin(lang2)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Language 3 check failed: expected 'Rust', got '");
                for (size i = 0; i < StrLen(lang3); i++) {
                    WriteFmt("{c}", StrBegin(lang3)[i]);
                }
                WriteFmt("'\n");
            WriteFmt("[DEBUG] User name check failed: expected 'Charlie', got '");
            for (size i = 0; i < StrLen(&data.user.name); i++) {
                WriteFmt("{c}", StrBegin(&data.user.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] User email check failed: expected 'charlie@example.com', got '");
            for (size i = 0; i < StrLen(&data.user.email); i++) {
                WriteFmt("{c}", StrBegin(&data.user.email)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Product name check failed: expected 'Laptop', got '");
            for (size i = 0; i < StrLen(&product.name); i++) {
                WriteFmt("{c}", StrBegin(&product.name)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Tag 1 check failed: expected 'electronics', got '");
                for (size i = 0; i < StrLen(tag1); i++) {
                    WriteFmt("{c}", StrBegin(tag1)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Tag 2 check failed: expected 'computers', got '");
                for (size i = 0; i < StrLen(tag2); i++) {
                    WriteFmt("{c}", StrBegin(tag2)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Tag 3 check failed: expected 'portable', got '");
                for (size i = 0; i < StrLen(tag3); i++) {
                    WriteFmt("{c}", StrBegin(tag3)[i]);
                }
                WriteFmt("'\n");
        // Remove spaces and newlines from both strings for comparison
        for (size i = 0; i < StrLen(output); i++) {
            char c = StrBegin(output)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&output_clean, c);
    
        for (size i = 0; i < StrLen(&expected_str); i++) {
            char c = StrBegin(&expected_str)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&expected_clean, c);
            WriteFmt("[DEBUG] Expected: '");
            for (u64 i = 0; i < StrLen(&expected_clean); i++) {
                WriteFmt("{c}", StrBegin(&expected_clean)[i]);
            }
            WriteFmtLn("'");
            WriteFmt("[DEBUG] Got: '");
            for (u64 i = 0; i < StrLen(&output_clean); i++) {
                WriteFmt("{c}", StrBegin(&output_clean)[i]);
            }
            WriteFmtLn("'");
    
        // For large numbers, just check that valid JSON was produced
        if (StrLen(&json) > 0 && StrBegin(&json)[0] == '{' && StrBegin(&json)[StrLen(&json) - 1] == '}') {
            WriteFmtLn("[DEBUG] Large numbers test passed - produced valid JSON structure");
        } else {
    
        // Just verify that valid JSON structure was produced
        if (StrLen(&json) > 0 && StrBegin(&json)[0] == '{' && StrBegin(&json)[StrLen(&json) - 1] == '}') {
            WriteFmtLn("[DEBUG] Special characters test passed - produced valid JSON");
        } else {
    
        // Verify valid JSON structure was produced
        if (StrLen(&json) > 0 && StrBegin(&json)[0] == '{' && StrBegin(&json)[StrLen(&json) - 1] == '}') {
            WriteFmtLn("[DEBUG] Escape sequences test passed - produced valid JSON");
        } else {
    
        // Check for reasonable float formatting (exact precision may vary)
        if (StrLen(&json) > 0 && StrBegin(&json)[0] == '{' && StrBegin(&json)[StrLen(&json) - 1] == '}') {
            WriteFmtLn("[DEBUG] Boundary floats test passed - JSON: {}", json);
        } else {
        // Remove whitespace from both strings for comparison
        for (u64 i = 0; i < StrLen(output); i++) {
            char c = StrBegin(output)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&output_clean, c);
    
        for (u64 i = 0; i < StrLen(&expected_str); i++) {
            char c = StrBegin(&expected_str)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&expected_clean, c);
            WriteFmt("[DEBUG] Expected: '");
            for (u64 i = 0; i < StrLen(&expected_clean); i++) {
                WriteFmt("{c}", StrBegin(&expected_clean)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Got: '");
            for (u64 i = 0; i < StrLen(&output_clean); i++) {
                WriteFmt("%c", StrBegin(&output_clean)[i]);
            }
            WriteFmt("'\n");
                StrAppendFmt(&source_key, "{}", source_id);
    
                JW_OBJ_KV(json, StrBegin(&source_key), {
                    if (VecLen(&response.data) > 0) {
                        AnnSymbol *s          = &VecAt(&response.data, 0);
                        StrAppendFmt(&target_key, "{}", s->target_function_id);
    
                        JW_OBJ_KV(json, StrBegin(&target_key), {
                            JW_FLT_KV(json, "distance", s->distance);
                            JW_INT_KV(json, "nearest_neighbor_analysis_id", s->analysis_id);
                    StrAppendFmt(&source_key, "{}", symbol.source_function_id);
    
                    JW_OBJ_KV(json, StrBegin(&source_key), {
                Str target_key = StrInit(&alloc);
                StrAppendFmt(&target_key, "{}", symbol.target_function_id);
                StrAppendFmt(&target_key, "{}", symbol.target_function_id);
    
                JW_OBJ_KV(json, StrBegin(&target_key), {
                    JW_FLT_KV(json, "distance", symbol.distance);
                    JW_STR_KV(json, "name", symbol.function_name);
            WriteFmt("[DEBUG] Name check failed: expected 'test', got '");
            for (size i = 0; i < StrLen(&data.name); i++) {
                WriteFmt("{c}", StrBegin(&data.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Profile name check failed: expected 'Alice', got '");
            for (u64 i = 0; i < StrLen(&data.user.profile.name); i++) {
                WriteFmt("{}", StrBegin(&data.user.profile.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Status check failed: expected 'active', got '");
            for (size i = 0; i < StrLen(&data.status); i++) {
                WriteFmt("{}", StrBegin(&data.status)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Engineering head check failed: expected 'John', got '");
            for (size i = 0; i < StrLen(&data.company.departments.engineering.head); i++) {
                WriteFmt("{c}", StrBegin(&data.company.departments.engineering.head)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Company name check failed: expected 'TechCorp', got '");
            for (size i = 0; i < StrLen(&data.company.name); i++) {
                WriteFmt("{c}", StrBegin(&data.company.name)[i]);
            }
            WriteFmt("'\n");
            JR_OBJ_KV(si, "functions", {
                // First level: source function ID from key
                u64 source_function_id = (u64)ZstrToI64(StrBegin(&key), NULL);
                JR_OBJ(si, {
                    // Second level: target function ID from key
                JR_OBJ(si, {
                    // Second level: target function ID from key
                    u64 target_function_id = (u64)ZstrToI64(StrBegin(&key), NULL);
    
                    // Properly initialize all Str fields
            if (response.status) {
                JR_OBJ_KV(si, "data", {
                    u64 source_function_id = (u64)ZstrToI64(StrBegin(&key), NULL);
                    JR_OBJ(si, {
                        // Properly initialize all Str fields
                        sym.function_mangled_name = StrInit(&alloc);
                        sym.source_function_id    = source_function_id;
                        sym.target_function_id    = (u64)ZstrToI64(StrBegin(&key), NULL);
    
                        JR_OBJ(si, {
            WriteFmt("[DEBUG] Message check failed: expected 'Success', got '");
            for (size i = 0; i < StrLen(&response.message); i++) {
                WriteFmt("{c}", StrBegin(&response.message)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Analysis name check failed: expected 'test_analysis', got '");
                for (size i = 0; i < StrLen(&sym->analysis_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->analysis_name)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] SHA256 check failed: expected 'abc123', got '");
                for (size i = 0; i < StrLen(&sym->sha256); i++) {
                    WriteFmt("{c}", StrBegin(&sym->sha256)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Mangled name check failed: expected '_Z4main', got '");
                for (size i = 0; i < StrLen(&sym->function_mangled_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->function_mangled_name)[i]);
                }
                WriteFmt("'\n");
            WriteFmt("[DEBUG] Function name check failed: expected 'test_func', got '");
            for (size i = 0; i < StrLen(&info.name); i++) {
                WriteFmt("{}", StrBegin(&info.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Model name check failed: expected 'test_model', got '");
            for (size i = 0; i < StrLen(&info.name); i++) {
                WriteFmt("{}", StrBegin(&info.name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Binary name check failed: expected 'test_binary', got '");
            for (size i = 0; i < StrLen(&result.binary_name); i++) {
                WriteFmt("{c}", StrBegin(&result.binary_name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] SHA256 check failed: expected 'abc123', got '");
            for (size i = 0; i < StrLen(&result.sha256); i++) {
                WriteFmt("{c}", StrBegin(&result.sha256)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Model name check failed: expected 'test_model', got '");
            for (size i = 0; i < StrLen(&result.model_name); i++) {
                WriteFmt("{c}", StrBegin(&result.model_name)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Owned by check failed: expected 'user1', got '");
            for (size i = 0; i < StrLen(&result.owned_by); i++) {
                WriteFmt("{c}", StrBegin(&result.owned_by)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Parsed status: {}, message: '", response.status ? "true" : "false");
            for (size i = 0; i < StrLen(&response.message); i++) {
                WriteFmt("{c}", StrBegin(&response.message)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Status is true, parsing data...\n");
                JR_OBJ_KV(si, "data", {
                    u64 source_function_id = (u64)ZstrToI64(StrBegin(&key), NULL);
                    WriteFmt("[DEBUG] Source function ID from key: {}\n", source_function_id);
                    JR_OBJ(si, {
                        sym.function_mangled_name = StrInit(&alloc);
                        sym.source_function_id    = source_function_id;
                        sym.target_function_id    = (u64)ZstrToI64(StrBegin(&key), NULL);
    
                        WriteFmt("[DEBUG] Target function ID from key: {}\n", sym.target_function_id);
            WriteFmt("[DEBUG] Message check failed: expected 'Success', got '");
            for (size i = 0; i < StrLen(&response.message); i++) {
                WriteFmt("{c}", StrBegin(&response.message)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Analysis name check failed: expected 'test_analysis', got '");
                for (size i = 0; i < StrLen(&sym->analysis_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->analysis_name)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] SHA256 check failed: expected 'abc123', got '");
                for (size i = 0; i < StrLen(&sym->sha256); i++) {
                    WriteFmt("{c}", StrBegin(&sym->sha256)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Mangled name check failed: expected '_Z4main', got '");
                for (size i = 0; i < StrLen(&sym->function_mangled_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->function_mangled_name)[i]);
                }
                WriteFmt("'\n");
            WriteFmt("[DEBUG] Parsed status: {}, message: '", response.status ? "true" : "false");
            for (size i = 0; i < StrLen(&response.message); i++) {
                WriteFmt("{c}", StrBegin(&response.message)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Status is true, parsing data...\n");
                JR_OBJ_KV(si, "data", {
                    u64 source_function_id = (u64)ZstrToI64(StrBegin(&key), NULL);
                    WriteFmt("[DEBUG] Source function ID from key: {}\n", source_function_id);
                    JR_OBJ(si, {
                        sym.function_mangled_name = StrInit(&alloc);
                        sym.source_function_id    = source_function_id;
                        sym.target_function_id    = (u64)ZstrToI64(StrBegin(&key), NULL);
    
                        WriteFmt("[DEBUG] Target function ID from key: {}\n", sym.target_function_id);
            WriteFmt("[DEBUG] Message check failed: expected 'Success', got '");
            for (u64 i = 0; i < StrLen(&response.message); i++) {
                WriteFmt("{c}", StrBegin(&response.message)[i]);
            }
            WriteFmt("'\n");
                WriteFmt("[DEBUG] Analysis name check failed: expected 'test_analysis', got '");
                for (size i = 0; i < StrLen(&sym->analysis_name); i++) {
                    WriteFmt("{}", StrBegin(&sym->analysis_name)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Function name check failed: expected 'main_func', got '");
                for (size i = 0; i < StrLen(&sym->function_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->function_name)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] SHA256 check failed: expected 'abc123', got '");
                for (size i = 0; i < StrLen(&sym->sha256); i++) {
                    WriteFmt("{}", StrBegin(&sym->sha256)[i]);
                }
                WriteFmt("'\n");
                WriteFmt("[DEBUG] Mangled name check failed: expected '_Z4main', got '");
                for (size i = 0; i < StrLen(&sym->function_mangled_name); i++) {
                    WriteFmt("{c}", StrBegin(&sym->function_mangled_name)[i]);
                }
                WriteFmt("'\n");
        // Remove spaces and newlines from both strings for comparison
        for (size i = 0; i < StrLen(output); i++) {
            char c = StrBegin(output)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&output_clean, c);
    
        for (size i = 0; i < StrLen(&expected_str); i++) {
            char c = StrBegin(&expected_str)[i];
            if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
                StrPushBackR(&expected_clean, c);
            WriteFmt("[DEBUG] Expected: '");
            for (size i = 0; i < StrLen(&expected_clean); i++) {
                WriteFmt("{c}", StrBegin(&expected_clean)[i]);
            }
            WriteFmt("'\n");
            WriteFmt("[DEBUG] Got: '");
            for (size i = 0; i < StrLen(&output_clean); i++) {
                WriteFmt("{c}", StrBegin(&output_clean)[i]);
            }
            WriteFmt("'\n");
        Zstr msg_want  = "Hello, \"World\"!";
        Zstr data_want = "line1\nline2\ttab";
        if (StrLen(&obj.path) != ZstrLen(path_want) || MemCompare(StrBegin(&obj.path), path_want, StrLen(&obj.path)) != 0) {
            WriteFmtLn("[DEBUG] Special characters FAILED: path content wrong");
            success = false;
        }
        if (StrLen(&obj.message) != ZstrLen(msg_want) ||
            MemCompare(StrBegin(&obj.message), msg_want, StrLen(&obj.message)) != 0) {
            WriteFmtLn("[DEBUG] Special characters FAILED: message content wrong");
            success = false;
            success = false;
        }
        if (StrLen(&obj.data) != ZstrLen(data_want) || MemCompare(StrBegin(&obj.data), data_want, StrLen(&obj.data)) != 0) {
            WriteFmtLn("[DEBUG] Special characters FAILED: data content wrong");
            success = false;
        };
        for (u64 i = 0; i < sizeof(expect) / sizeof(expect[0]); i++) {
            if (StrLen(expect[i].got) != 1 || *StrBegin(expect[i].got) != expect[i].want) {
                WriteFmtLn(
                    "[DEBUG] Escape sequences FAILED: {} decoded wrong (len={})",
            WriteFmt(
                "[DEBUG] Whitespace variations test passed - name: {}, value: {}, flag: {}\n",
                StrBegin(&obj.name),
                obj.value,
                obj.flag ? "true" : "false"
            WriteFmt(
                "[DEBUG] Whitespace variations test FAILED - name: {}, value: {}, flag: {}\n",
                StrBegin(&obj.name),
                obj.value,
                obj.flag ? "true" : "false"
                success = false;
            }
            if (StrLen(&out) != 5 || MemCompare(StrBegin(&out), "plain", 5) != 0) {
                WriteFmtLn("[DEBUG] JReadString decoded plain string wrong: len={}", StrLen(&out));
                success = false;
                original.temperature,
                original.enabled ? "true" : "false",
                StrBegin(&original.message)
            );
            WriteFmtLn(
                parsed.temperature,
                parsed.enabled ? "true" : "false",
                StrBegin(&parsed.message)
            );
            success = false;
    
        result = result && stored_host;
        result = result && (StrBegin(&host_copy) != NULL);
        result = result && (StrBegin(&host_copy) != StrBegin(stored_host));
        // exact content (StrCmp below) subsumes any non-emptiness check.
        result = result && stored_host;
        result = result && (StrBegin(&host_copy) != NULL);
        result = result && (StrBegin(&host_copy) != StrBegin(stored_host));
        // exact content (StrCmp below) subsumes any non-emptiness check.
        result = result && (StrCmp(&host_copy, "localhost") == 0);
        result = result && (StrCmp(stored_host, "localhost") == 0);
    
        StrBegin(&host_copy)[0] = 'L';
    
        result = result && (StrCmp(&host_copy, "Localhost") == 0);
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