25 0.2 0.5 / none) l a b / alpha)`, `oklab(0.25 0.2 0.5 / 0)`);

    // lab and oklab tests that require different results due to percent scaling differences.
    test_valid_value(`color`, `lab(from lab(.7 45 30) alpha b a / l)`, `lab(100 30 45 / 0.7)`);
    test_valid_value(`color`, `lab(from lab(.7 45 30) alpha a b / alpha)`, `lab(100 45 30)`);
    test_valid_value(`color`, `lab(from lab(.7 45 30) alpha a a / alpha)`, `lab(100 45 45)`);
    test_valid_value(`color`, `lab(from lab(.7 45 30 / 40%) alpha b a