{resultColorSpace} 7 0 100 / 0.4)`);
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -20.5 100 / 40%) ${colorSpace} x y 0 / alpha)`,                `color(${resultColorSpace} 7 -20.5 0 / 0.4)`);
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -20.5 100 / 40%) ${colorSpace} x y z / 0)`,                    `color(${resultColorSpace} 7 -20.5 100 / 0)`);

        // Testing replacement with a constant.
        test_valid_value(`color`, `color(from color(${colorSpace} 7 -2