c(100% + 100%)", "calc(200%)");
test_valid_value("opacity", "calc(-0.5 - 0.5)", "calc(-1)");
test_valid_value("opacity", "calc(0.25 * 2)", "calc(0.5)");
test_valid_value("opacity", "calc(1 + 1)", "calc(2)");
test_valid_value("opacity", "clamp(50%, 0%, 70%)", "calc(50%)");
test_valid_value("opacity", "clamp(50%, 80%, 70%)", "calc(70%)");
test_valid_value("opacity", "clamp(50%, 60%, 70%)", "calc(60%)");
test_valid_value("opacity", "min(50%, 0%)", "calc(0%)");
test_valid_value("opacity", "min(0%, 50%)", "calc(