Split implementations from generic code

controllers/nginx/pkg/cmd/controller/utils_test.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2015 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 main
+
+import "testing"
+
+func TestDiff(t *testing.T) {
+	tests := []struct {
+		a     []byte
+		b     []byte
+		empty bool
+	}{
+		{[]byte(""), []byte(""), true},
+		{[]byte("a"), []byte("a"), true},
+		{[]byte("a"), []byte("b"), false},
+	}
+
+	for _, test := range tests {
+		b, err := diff(test.a, test.b)
+		if err != nil {
+			t.Fatalf("unexpected error returned: %v", err)
+		}
+		if len(b) == 0 && !test.empty {
+			t.Fatalf("expected empty but returned %s", b)
+		}
+	}
+}