}
	out, err := cmd.CombinedOutput()
	if string(out) != "OK\n" {
		t.Errorf("%s", string(out))
	}
	if err != nil {
		t.Errorf("%s", err)
	}
}

func mustHaveCxx(t *testing.T) {
	// Ask the go tool for the CXX it's configured to use.
	cxx, err := exec.Command("go", "env", "CXX").CombinedOutput()
	if err != nil {
		t.Fatalf("go env CXX failed: %s", err)
	}
	args, err := quoted.Split(string(cxx))

		return nil, fmt.Errorf("go language version %s is not a toolchain version", rev)
	}

	// Check that the underlying toolchain exists.
	// We always ask about linux-amd64 because that one
	// has always existed and is likely to always exist in the future.
	// This avoids different behavior validating go versions on different