.45 0.45 / 0.4)`);

    // Testing with calc().
    test_valid_value(`color`, `oklch(from oklch(0.7 0.45 30) calc(l) calc(c) calc(h))`, `oklch(0.7 0.45 30)`);
    test_valid_value(`color`, `oklch(from oklch(0.7 0.45 30 / 40%) calc(l) calc(c) calc(h) / calc(alpha))`, `oklch(0.7 0.45 30 / 0.4)`);

    // Testing with 'none'.
    test_valid_value(`color`, `oklch(from oklch(0.7 0.45 30) none none none)`,                                   `oklch(none none none)`);
    test_valid_value(`color`, `oklch(from oklch(