// ExpectError calls t.Fatalf if the error does not contain a substr match. // If substr is empty, a nil error is expected. // It is useful to call ExpectError from subtests. func ExpectError(t *testing.T, err error, substr string) { … } // SkipRest returns true if there was a non-nil error or if we expected an error that didn't happen, // and logs the appropriate error on the test object. // The return value indicates whether we should skip the rest of the test case due to the error result. func SkipRest(t *testing.T, desc string, err error, contains string) bool { … }