t.Fatalf("error was not IncompatibleUsage: %v", err)
	}
}

func expectAuthorityUnknown(t *testing.T, err error) {
	e, ok := err.(UnknownAuthorityError)
	if !ok {
		t.Fatalf("error was not UnknownAuthorityError: %v", err)
	}
	if e.Cert == nil {
		t.Fatalf("error was UnknownAuthorityError, but missing Cert: %v", err)
	}
}

func expectHashError(t *testing.T, err error) {
	if err == nil {