build error utility package to replace juju/errors

Signed-off-by: Bruce Ma <brucema19901024@gmail.com>

pkg/errors/errors_test.go

@@ -0,0 +1,96 @@
+// Copyright 2020 CNI authors
+//
+// 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package errors
+
+import (
+	"errors"
+	"reflect"
+	"testing"
+)
+
+func TestAnnotate(t *testing.T) {
+	tests := []struct {
+		name           string
+		existingErr    error
+		contextMessage string
+		expectedErr    error
+	}{
+		{
+			"nil error",
+			nil,
+			"context",
+			nil,
+		},
+		{
+			"normal case",
+			errors.New("existing error"),
+			"context",
+			errors.New("context: existing error"),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if !reflect.DeepEqual(Annotatef(test.existingErr, test.contextMessage), test.expectedErr) {
+				t.Errorf("test case %s fails", test.name)
+				return
+			}
+		})
+	}
+}
+
+func TestAnnotatef(t *testing.T) {
+	tests := []struct {
+		name           string
+		existingErr    error
+		contextMessage string
+		contextArgs    []interface{}
+		expectedErr    error
+	}{
+		{
+			"nil error",
+			nil,
+			"context",
+			nil,
+			nil,
+		},
+		{
+			"normal case",
+			errors.New("existing error"),
+			"context",
+			nil,
+			errors.New("context: existing error"),
+		},
+		{
+			"normal case with args",
+			errors.New("existing error"),
+			"context %s %d",
+			[]interface{}{
+				"arg",
+				100,
+			},
+			errors.New("context arg 100: existing error"),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if !reflect.DeepEqual(Annotatef(test.existingErr, test.contextMessage, test.contextArgs...), test.expectedErr) {
+				t.Errorf("test case %s fails", test.name)
+				return
+			}
+		})
+	}
+}