Add missing tests for bucket util (#565)

* Add CheckDeepEqual test util

* Fix for srcContext with slash suffix

* Add tests for bucket_util.go

pkg/util/bucket_util_test.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2018 Google LLC
+
+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 util
+
+import (
+	"testing"
+
+	"github.com/GoogleContainerTools/kaniko/pkg/constants"
+	"github.com/GoogleContainerTools/kaniko/testutil"
+)
+
+func Test_GetBucketAndItem(t *testing.T) {
+	tests := []struct {
+		name           string
+		context        string
+		expectedBucket string
+		expectedItem   string
+	}{
+		{
+			name:           "three slashes",
+			context:        "test1/test2/test3",
+			expectedBucket: "test1",
+			expectedItem:   "test2/test3",
+		},
+		{
+			name:           "two slashes",
+			context:        "test1/test2",
+			expectedBucket: "test1",
+			expectedItem:   "test2",
+		},
+		{
+			name:           "one slash",
+			context:        "test1/",
+			expectedBucket: "test1",
+			expectedItem:   constants.ContextTar,
+		},
+		{
+			name:           "zero slash",
+			context:        "test1",
+			expectedBucket: "test1",
+			expectedItem:   constants.ContextTar,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			gotBucket, gotItem := GetBucketAndItem(test.context)
+			testutil.CheckDeepEqual(t, test.expectedBucket, gotBucket)
+			testutil.CheckDeepEqual(t, test.expectedItem, gotItem)
+		})
+	}
+
+}