}
    
    bool StrContains(const Str *s, const Str *key) {
        if (!key) {
            LOG_FATAL("Invalid arguments");

    // Test string contains/index functions
    bool test_str_contains_index(void) {
        WriteFmt("Testing StrContains and StrIndexOf variants\n");
    
        Str haystack = StrInitFromZstr("Hello World");

        Str needle   = StrInitFromZstr("World");
    
        bool result = StrContains(&haystack, &needle);
        result      = result && StrContainsZstr(&haystack, "Hello");
        result      = result && StrContainsCstr(&haystack, "lo Wo", 5);