}

    // Edge/Invalid: empty string is invalid for valueOf
    @ParameterizedTest
    @EmptySource
    @DisplayName("valueOf(\"\") throws IllegalArgumentException for empty input")
    void valueOfRejectsEmpty(String empty) {
        assertThrows(IllegalArgumentException.class, () -> RequestParam.valueOf(empty));
    }

    // Invalid: null is not allowed for valueOf
    @ParameterizedTest
    @NullSource