Modify hash to be computed using spew library so that nested object values are used instead of pointer

pkg/util/hash_test.go

@@ -0,0 +1,63 @@
+/*
+Copyright 2014 Google Inc. 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 util
+
+import (
+	"hash/adler32"
+	"testing"
+)
+
+type wheel struct {
+	radius uint32
+}
+
+type unicycle struct {
+	primaryWheel   *wheel
+	licencePlateID string
+}
+
+func TestDeepObjectPointer(t *testing.T) {
+	// Arrange
+	wheel1 := wheel{radius: 17}
+	wheel2 := wheel{radius: 22}
+	wheel3 := wheel{radius: 17}
+
+	myUni1 := unicycle{licencePlateID: "blah", primaryWheel: &wheel1}
+	myUni2 := unicycle{licencePlateID: "blah", primaryWheel: &wheel2}
+	myUni3 := unicycle{licencePlateID: "blah", primaryWheel: &wheel3}
+
+	hasher1 := adler32.New()
+	hasher2 := adler32.New()
+	hasher3 := adler32.New()
+
+	// Act
+	DeepHashObject(hasher1, myUni1)
+	hash1 := hasher1.Sum32()
+	DeepHashObject(hasher2, myUni2)
+	hash2 := hasher2.Sum32()
+	DeepHashObject(hasher3, myUni3)
+	hash3 := hasher3.Sum32()
+
+	// Assert
+	if hash1 == hash2 {
+		t.Errorf("hash1 (%d) and hash2(%d) must be different because they have different values for wheel size", hash1, hash2)
+	}
+
+	if hash1 != hash3 {
+		t.Errorf("hash1 (%d) and hash3(%d) must be the same because although they point to different objects, they have the same values for wheel size", hash1, hash3)
+	}
+}