Add strings pkg to hold strings utils

Replace funtions with strings pkg

Fix all references and rename the pkg

pkg/util/strings/strings_test.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2014 The Kubernetes Authors 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 strings
+
+import (
+	"testing"
+)
+
+func TestSplitQualifiedName(t *testing.T) {
+	testCases := []struct {
+		input  string
+		output []string
+	}{
+		{"kubernetes.io/blah", []string{"kubernetes.io", "blah"}},
+		{"blah", []string{"", "blah"}},
+		{"kubernetes.io/blah/blah", []string{"kubernetes.io", "blah"}},
+	}
+	for i, tc := range testCases {
+		namespace, name := SplitQualifiedName(tc.input)
+		if namespace != tc.output[0] || name != tc.output[1] {
+			t.Errorf("case[%d]: expected (%q, %q), got (%q, %q)", i, tc.output[0], tc.output[1], namespace, name)
+		}
+	}
+}
+func TestJoinQualifiedName(t *testing.T) {
+	testCases := []struct {
+		input  []string
+		output string
+	}{
+		{[]string{"kubernetes.io", "blah"}, "kubernetes.io/blah"},
+		{[]string{"blah", ""}, "blah"},
+		{[]string{"kubernetes.io", "blah"}, "kubernetes.io/blah"},
+	}
+	for i, tc := range testCases {
+		res := JoinQualifiedName(tc.input[0], tc.input[1])
+		if res != tc.output {
+			t.Errorf("case[%d]: expected %q, got %q", i, tc.output, res)
+		}
+	}
+}