Add HandleError input parameter check (#798)

There could be a panic on HandleError logging functionality. Add test
coverage for that.

pkg/util/runtime/runtime.go

@@ -52,8 +52,10 @@ func init() {
 // HandleError wraps runtime.HandleError so that it is possible to
 // use WithField with logrus.
 func HandleError(logger *logrus.Entry, err error) {
-	// it's a bit of a double handle, but I can't see a better way to do it
-	logger.WithError(err).Error()
+	if logger != nil {
+		// it's a bit of a double handle, but I can't see a better way to do it
+		logger.WithError(err).Error()
+	}
 	runtime.HandleError(err)
 }
 

pkg/util/runtime/runtime_test.go

@@ -0,0 +1,46 @@
+// Copyright 2019 Google LLC All Rights Reserved.
+//
+// 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 runtime handles runtime errors
+// Wraps and reconfigures functionality in apimachinery/pkg/runtime
+package runtime
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/util/runtime"
+)
+
+func TestHandleError(t *testing.T) {
+	old := runtime.ErrorHandlers
+	defer func() { runtime.ErrorHandlers = old }()
+	var result error
+	runtime.ErrorHandlers = []func(error){
+		func(err error) {
+			result = err
+		},
+	}
+	HandleError(nil, nil)
+	assert.Nil(t, result, "No Errors for now")
+
+	err := fmt.Errorf("test")
+	//test nil logger
+	logger := NewLoggerWithSource("test")
+	HandleError(logger.WithError(err), err)
+	if result != err {
+		t.Errorf("did not receive custom handler")
+	}
+}