     // Testing valid permutation (types match).
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -20.5 100) ${colorSpace} y z x)`,                              `color(${resultColorSpace} -20.5 100 7)`);
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -20.5 100) ${colorSpace} x x x / x)`,                          `color(${resultColorSpace} 7 7 7)`);
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -20.5 100 / 40%) ${colorSpace} y z x)`,              