add unit test

engine/framework/fake/errors.go

@@ -14,6 +14,7 @@
 package fake
 
 import (
+	libErrors "errors"
 	"fmt"
 	"regexp"
 
@@ -32,14 +33,13 @@ func NewJobUnRetryableError(errIn error) *JobUnRetryableError {
 	}
 }
 
-// Message returns raw error message of JobUnRetryableError
-func (e *JobUnRetryableError) Message() string {
-	return "fake job unretryable error"
-}
-
 // Error implements error interface
 func (e *JobUnRetryableError) Error() string {
-	return fmt.Sprintf("%s: %s", e.Message(), e.errIn)
+	return fmt.Sprintf("%s: %s", e.message(), e.errIn)
+}
+
+func (e *JobUnRetryableError) message() string {
+	return "fake job unretryable error"
 }
 
 const fakeJobErrorFormat = "fake job unretryable error: (.*)"
@@ -48,9 +48,15 @@ var fakeJobErrorRegexp = regexp.MustCompile(fakeJobErrorFormat)
 
 // ToFakeJobError tries best to construct a fake job error from an error object
 func ToFakeJobError(err error) error {
+	var errOut *JobUnRetryableError
+	if libErrors.As(err, &errOut) {
+		return err
+	}
+
 	subMatch := fakeJobErrorRegexp.FindStringSubmatch(err.Error())
 	if len(subMatch) > 1 {
 		return NewJobUnRetryableError(errors.New(subMatch[1]))
 	}
+
 	return err
 }

engine/framework/fake/errors_test.go

@@ -0,0 +1,33 @@
+// Copyright 2022 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fake
+
+import (
+	"testing"
+
+	"github.com/pingcap/errors"
+	"github.com/stretchr/testify/require"
+)
+
+func TestToFakeJobError(t *testing.T) {
+	t.Parallel()
+
+	normalErr := errors.New("normal error")
+	fakeJobErr := NewJobUnRetryableError(normalErr)
+	errFromPlainText := errors.New(fakeJobErr.Error())
+
+	require.Equal(t, normalErr, ToFakeJobError(normalErr))
+	require.Equal(t, fakeJobErr, ToFakeJobError(fakeJobErr))
+	require.EqualError(t, ToFakeJobError(errFromPlainText), fakeJobErr.Error())
+}