package errorhandler import ( "errors" "fmt" "testing" ) func TestCheck(t *testing.T) { text := "text before error" err := "test error" expected := fmt.Errorf("%s, error is:\n\t-> %s", text, err) result := FormatError(text, errors.New(err)) fmt.Println(result, expected) if result.Error() != expected.Error() { t.Fatalf("expected (%s) is different from result (%s)", expected.Error(), result.Error()) } }