diff --git a/core/pkg/strings/string_test.go b/core/pkg/strings/string_test.go
new file mode 100644
index 000000000..2de3e4c51
--- /dev/null
+++ b/core/pkg/strings/string_test.go
@@ -0,0 +1,45 @@
+/*
+Copyright 2017 The Kubernetes 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 strings
+
+import (
+	"testing"
+)
+
+var testDatas = []struct {
+	a     string
+	slice []string
+	er    bool
+}{
+	{"first", []string{"first", "second"}, true},
+	{"FIRST", []string{"first", "second"}, false},
+	{"third", []string{"first", "second"}, false},
+	{"first", nil, false},
+
+	{"", []string{"first", "second"}, false},
+	{"", []string{"first", "second", ""}, true},
+	{"", nil, false},
+}
+
+func TestStringInSlice(t *testing.T) {
+	for _, testData := range testDatas {
+		r := StringInSlice(testData.a, testData.slice)
+		if r != testData.er {
+			t.Errorf("getted result is '%t', but expected is '%t'", r, testData.er)
+		}
+	}
+}