test_valid_value(`color`, `oklch(from oklch(none none none / none) l c h / alpha)`,                        `oklch(0 0 0 / 0)`);
    test_valid_value(`color`, `oklch(from oklch(0.7 none 30) l c h)`,                                          `oklch(0.7 0 30)`);
    test_valid_value(`color`, `oklch(from oklch(0.7 0.45 30 / none) l c h / alpha)`,                             `oklch(0.7 0.45 30 / 0)`);

    // lch and oklch tests that require different results due to percent scaling differences.
    test_valid_val