Add dictionary comparing functions and unit tests

base/values_unittest.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class ValuesTest: public testing::Test {
+ protected:
+  void CompareDictionariesAndCheckResult(
+      const DictionaryValue* dict1,
+      const DictionaryValue* dict2,
+      const char* expected_paths[],
+      size_t expected_paths_count) {
+    std::vector<std::string> differing_paths;
+    std::vector<std::string> expected_paths_vector(expected_paths,
+        expected_paths+expected_paths_count);
+    // All comparisons should be commutative, check dict1 against dict2
+    // and vice-versa.
+    dict1->GetDifferingPaths(dict2, &differing_paths);
+    ASSERT_EQ(expected_paths_count, differing_paths.size());
+    EXPECT_TRUE(equal(differing_paths.begin(), differing_paths.end(),
+                      expected_paths_vector.begin()));
+    dict2->GetDifferingPaths(dict1, &differing_paths);
+    ASSERT_EQ(expected_paths_count, differing_paths.size());
+    EXPECT_TRUE(equal(differing_paths.begin(), differing_paths.end(),
+                      expected_paths_vector.begin()));
+  }
 };
 
 // TODO(viettrungluu): I changed the keys for DictionaryValue from std::wstring
 // to std::string. I've temporarily kept the old methods taking std::wstring for
 // compatibility. The ...Deprecated tests are the old tests which use these
 // methods, and remain to test compatibility. They will be removed once the old
 // methods are removed. There are also parts of tests marked DEPRECATED which
 // are to be deleted.
 
-TEST(ValuesTest, Basic) {
+TEST_F(ValuesTest, Basic) {
   // Test basic dictionary getting/setting
   DictionaryValue settings;
   std::string homepage = "http://google.com";
   ASSERT_FALSE(settings.GetString("global.homepage", &homepage));
   ASSERT_EQ(std::string("http://google.com"), homepage);
 
   ASSERT_FALSE(settings.Get("global", NULL));
   settings.Set("global", Value::CreateBooleanValue(true));
   ASSERT_TRUE(settings.Get("global", NULL));
   settings.SetString("global.homepage", "http://scurvy.com");
@@ skipping 23 matching lines @@
   ASSERT_TRUE(bookmark_list->GetDictionary(0, &bookmark));
   std::string bookmark_name = "Unnamed";
   ASSERT_TRUE(bookmark->GetString("name", &bookmark_name));
   ASSERT_EQ(std::string("Froogle"), bookmark_name);
   std::string bookmark_url;
   ASSERT_TRUE(bookmark->GetString("url", &bookmark_url));
   ASSERT_EQ(std::string("http://froogle.com"), bookmark_url);
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, BasicDeprecated) {
+TEST_F(ValuesTest, BasicDeprecated) {
   // Test basic dictionary getting/setting
   DictionaryValue settings;
   std::wstring homepage = L"http://google.com";
   ASSERT_FALSE(
     settings.GetString(L"global.homepage", &homepage));
   ASSERT_EQ(std::wstring(L"http://google.com"), homepage);
 
   ASSERT_FALSE(settings.Get(L"global", NULL));
   settings.Set(L"global", Value::CreateBooleanValue(true));
   ASSERT_TRUE(settings.Get(L"global", NULL));
@@ skipping 24 matching lines @@
   ASSERT_EQ(1U, bookmark_list->GetSize());
   ASSERT_TRUE(bookmark_list->GetDictionary(0, &bookmark));
   std::wstring bookmark_name = L"Unnamed";
   ASSERT_TRUE(bookmark->GetString(L"name", &bookmark_name));
   ASSERT_EQ(std::wstring(L"Froogle"), bookmark_name);
   std::wstring bookmark_url;
   ASSERT_TRUE(bookmark->GetString(L"url", &bookmark_url));
   ASSERT_EQ(std::wstring(L"http://froogle.com"), bookmark_url);
 }
 
-TEST(ValuesTest, List) {
+TEST_F(ValuesTest, List) {
   scoped_ptr<ListValue> mixed_list(new ListValue());
   mixed_list->Set(0, Value::CreateBooleanValue(true));
   mixed_list->Set(1, Value::CreateIntegerValue(42));
   mixed_list->Set(2, Value::CreateRealValue(88.8));
   mixed_list->Set(3, Value::CreateStringValue("foo"));
   ASSERT_EQ(4u, mixed_list->GetSize());
 
   Value *value = NULL;
   bool bool_value = false;
   int int_value = 0;
@@ skipping 14 matching lines @@
   ASSERT_TRUE(mixed_list->GetBoolean(0, &bool_value));
   ASSERT_EQ(true, bool_value);
   ASSERT_TRUE(mixed_list->GetInteger(1, &int_value));
   ASSERT_EQ(42, int_value);
   ASSERT_TRUE(mixed_list->GetReal(2, &double_value));
   ASSERT_EQ(88.8, double_value);
   ASSERT_TRUE(mixed_list->GetString(3, &string_value));
   ASSERT_EQ("foo", string_value);
 }
 
-TEST(ValuesTest, BinaryValue) {
+TEST_F(ValuesTest, BinaryValue) {
   char* buffer = NULL;
   // Passing a null buffer pointer doesn't yield a BinaryValue
   scoped_ptr<BinaryValue> binary(BinaryValue::Create(buffer, 0));
   ASSERT_FALSE(binary.get());
 
   // If you want to represent an empty binary value, use a zero-length buffer.
   buffer = new char[1];
   ASSERT_TRUE(buffer);
   binary.reset(BinaryValue::Create(buffer, 0));
   ASSERT_TRUE(binary.get());
@@ skipping 12 matching lines @@
   char stack_buffer[42];
   memset(stack_buffer, '!', 42);
   binary.reset(BinaryValue::CreateWithCopiedBuffer(stack_buffer, 42));
   ASSERT_TRUE(binary.get());
   ASSERT_TRUE(binary->GetBuffer());
   ASSERT_NE(stack_buffer, binary->GetBuffer());
   ASSERT_EQ(42U, binary->GetSize());
   ASSERT_EQ(0, memcmp(stack_buffer, binary->GetBuffer(), binary->GetSize()));
 }
 
-TEST(ValuesTest, StringValue) {
+TEST_F(ValuesTest, StringValue) {
   // Test overloaded CreateStringValue.
   scoped_ptr<Value> narrow_value(Value::CreateStringValue("narrow"));
   ASSERT_TRUE(narrow_value.get());
   ASSERT_TRUE(narrow_value->IsType(Value::TYPE_STRING));
   scoped_ptr<Value> utf16_value(
       Value::CreateStringValue(ASCIIToUTF16("utf16")));
   ASSERT_TRUE(utf16_value.get());
   ASSERT_TRUE(utf16_value->IsType(Value::TYPE_STRING));
 
   // Test overloaded GetString.
   std::string narrow = "http://google.com";
   string16 utf16 = ASCIIToUTF16("http://google.com");
   ASSERT_TRUE(narrow_value->GetAsString(&narrow));
   ASSERT_TRUE(narrow_value->GetAsString(&utf16));
   ASSERT_EQ(std::string("narrow"), narrow);
   ASSERT_EQ(ASCIIToUTF16("narrow"), utf16);
 
   ASSERT_TRUE(utf16_value->GetAsString(&narrow));
   ASSERT_TRUE(utf16_value->GetAsString(&utf16));
   ASSERT_EQ(std::string("utf16"), narrow);
   ASSERT_EQ(ASCIIToUTF16("utf16"), utf16);
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, StringValueDeprecated) {
+TEST_F(ValuesTest, StringValueDeprecated) {
   // Test overloaded CreateStringValue.
   scoped_ptr<Value> narrow_value(Value::CreateStringValue("narrow"));
   ASSERT_TRUE(narrow_value.get());
   ASSERT_TRUE(narrow_value->IsType(Value::TYPE_STRING));
   scoped_ptr<Value> wide_value(Value::CreateStringValue(L"wide"));
   ASSERT_TRUE(wide_value.get());
   ASSERT_TRUE(wide_value->IsType(Value::TYPE_STRING));
   scoped_ptr<Value> utf16_value(
       Value::CreateStringValue(ASCIIToUTF16("utf16")));
   ASSERT_TRUE(utf16_value.get());
@@ skipping 40 matching lines @@
   }
 
   ~DeletionTestValue() {
     *deletion_flag_ = true;
   }
 
  private:
   bool* deletion_flag_;
 };
 
-TEST(ValuesTest, ListDeletion) {
+TEST_F(ValuesTest, ListDeletion) {
   bool deletion_flag = true;
 
   {
     ListValue list;
     list.Append(new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
   }
   EXPECT_TRUE(deletion_flag);
 
   {
     ListValue list;
     list.Append(new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     list.Clear();
     EXPECT_TRUE(deletion_flag);
   }
 
   {
     ListValue list;
     list.Append(new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_TRUE(list.Set(0, Value::CreateNullValue()));
     EXPECT_TRUE(deletion_flag);
   }
 }
 
-TEST(ValuesTest, ListRemoval) {
+TEST_F(ValuesTest, ListRemoval) {
   bool deletion_flag = true;
   Value* removed_item = NULL;
 
   {
     ListValue list;
     list.Append(new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_EQ(1U, list.GetSize());
     EXPECT_FALSE(list.Remove(std::numeric_limits<size_t>::max(),
                              &removed_item));
@@ skipping 20 matching lines @@
     ListValue list;
     DeletionTestValue* value = new DeletionTestValue(&deletion_flag);
     list.Append(value);
     EXPECT_FALSE(deletion_flag);
     EXPECT_EQ(0, list.Remove(*value));
     EXPECT_TRUE(deletion_flag);
     EXPECT_EQ(0U, list.GetSize());
   }
 }
 
-TEST(ValuesTest, DictionaryDeletion) {
+TEST_F(ValuesTest, DictionaryDeletion) {
   std::string key = "test";
   bool deletion_flag = true;
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
   }
   EXPECT_TRUE(deletion_flag);
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     dict.Clear();
     EXPECT_TRUE(deletion_flag);
   }
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     dict.Set(key, Value::CreateNullValue());
     EXPECT_TRUE(deletion_flag);
   }
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, DictionaryDeletionDeprecated) {
+TEST_F(ValuesTest, DictionaryDeletionDeprecated) {
   std::wstring key = L"test";
   bool deletion_flag = true;
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
   }
   EXPECT_TRUE(deletion_flag);
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     dict.Clear();
     EXPECT_TRUE(deletion_flag);
   }
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     dict.Set(key, Value::CreateNullValue());
     EXPECT_TRUE(deletion_flag);
   }
 }
 
-TEST(ValuesTest, DictionaryRemoval) {
+TEST_F(ValuesTest, DictionaryRemoval) {
   std::string key = "test";
   bool deletion_flag = true;
   Value* removed_item = NULL;
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_TRUE(dict.HasKey(key));
     EXPECT_FALSE(dict.Remove("absent key", &removed_item));
@@ skipping 11 matching lines @@
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_TRUE(dict.HasKey(key));
     EXPECT_TRUE(dict.Remove(key, NULL));
     EXPECT_TRUE(deletion_flag);
     EXPECT_FALSE(dict.HasKey(key));
   }
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, DictionaryRemovalDeprecated) {
+TEST_F(ValuesTest, DictionaryRemovalDeprecated) {
   std::wstring key = L"test";
   bool deletion_flag = true;
   Value* removed_item = NULL;
 
   {
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_TRUE(dict.HasKey(key));
     EXPECT_FALSE(dict.Remove(L"absent key", &removed_item));
@@ skipping 10 matching lines @@
     DictionaryValue dict;
     dict.Set(key, new DeletionTestValue(&deletion_flag));
     EXPECT_FALSE(deletion_flag);
     EXPECT_TRUE(dict.HasKey(key));
     EXPECT_TRUE(dict.Remove(key, NULL));
     EXPECT_TRUE(deletion_flag);
     EXPECT_FALSE(dict.HasKey(key));
   }
 }
 
-TEST(ValuesTest, DictionaryWithoutPathExpansion) {
+TEST_F(ValuesTest, DictionaryWithoutPathExpansion) {
   DictionaryValue dict;
   dict.Set("this.is.expanded", Value::CreateNullValue());
   dict.SetWithoutPathExpansion("this.isnt.expanded", Value::CreateNullValue());
 
   EXPECT_FALSE(dict.HasKey("this.is.expanded"));
   EXPECT_TRUE(dict.HasKey("this"));
   Value* value1;
   EXPECT_TRUE(dict.Get("this", &value1));
   DictionaryValue* value2;
   ASSERT_TRUE(dict.GetDictionaryWithoutPathExpansion("this", &value2));
   EXPECT_EQ(value1, value2);
   EXPECT_EQ(1U, value2->size());
 
   EXPECT_TRUE(dict.HasKey("this.isnt.expanded"));
   Value* value3;
   EXPECT_FALSE(dict.Get("this.isnt.expanded", &value3));
   Value* value4;
   ASSERT_TRUE(dict.GetWithoutPathExpansion("this.isnt.expanded", &value4));
   EXPECT_EQ(Value::TYPE_NULL, value4->GetType());
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, DictionaryWithoutPathExpansionDeprecated) {
+TEST_F(ValuesTest, DictionaryWithoutPathExpansionDeprecated) {
   DictionaryValue dict;
   dict.Set(L"this.is.expanded", Value::CreateNullValue());
   dict.SetWithoutPathExpansion(L"this.isnt.expanded", Value::CreateNullValue());
 
   EXPECT_FALSE(dict.HasKey(L"this.is.expanded"));
   EXPECT_TRUE(dict.HasKey(L"this"));
   Value* value1;
   EXPECT_TRUE(dict.Get(L"this", &value1));
   DictionaryValue* value2;
   ASSERT_TRUE(dict.GetDictionaryWithoutPathExpansion(L"this", &value2));
   EXPECT_EQ(value1, value2);
   EXPECT_EQ(1U, value2->size());
 
   EXPECT_TRUE(dict.HasKey(L"this.isnt.expanded"));
   Value* value3;
   EXPECT_FALSE(dict.Get(L"this.isnt.expanded", &value3));
   Value* value4;
   ASSERT_TRUE(dict.GetWithoutPathExpansion(L"this.isnt.expanded", &value4));
   EXPECT_EQ(Value::TYPE_NULL, value4->GetType());
 }
 
-TEST(ValuesTest, DeepCopy) {
+TEST_F(ValuesTest, DeepCopy) {
   DictionaryValue original_dict;
   Value* original_null = Value::CreateNullValue();
   original_dict.Set("null", original_null);
   Value* original_bool = Value::CreateBooleanValue(true);
   original_dict.Set("bool", original_bool);
   Value* original_int = Value::CreateIntegerValue(42);
   original_dict.Set("int", original_int);
   Value* original_real = Value::CreateRealValue(3.14);
   original_dict.Set("real", original_real);
   Value* original_string = Value::CreateStringValue("hello");
@@ skipping 105 matching lines @@
   Value* copy_list_element_1;
   ASSERT_TRUE(copy_list->Get(1, &copy_list_element_1));
   ASSERT_TRUE(copy_list_element_1);
   ASSERT_NE(copy_list_element_1, original_list_element_1);
   int copy_list_element_1_value;
   ASSERT_TRUE(copy_list_element_1->GetAsInteger(&copy_list_element_1_value));
   ASSERT_EQ(1, copy_list_element_1_value);
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, DeepCopyDeprecated) {
+TEST_F(ValuesTest, DeepCopyDeprecated) {
   DictionaryValue original_dict;
   Value* original_null = Value::CreateNullValue();
   original_dict.Set(L"null", original_null);
   Value* original_bool = Value::CreateBooleanValue(true);
   original_dict.Set(L"bool", original_bool);
   Value* original_int = Value::CreateIntegerValue(42);
   original_dict.Set(L"int", original_int);
   Value* original_real = Value::CreateRealValue(3.14);
   original_dict.Set(L"real", original_real);
   Value* original_string = Value::CreateStringValue("hello");
@@ skipping 123 matching lines @@
 
   Value* copy_list_element_1;
   ASSERT_TRUE(copy_list->Get(1, &copy_list_element_1));
   ASSERT_TRUE(copy_list_element_1);
   ASSERT_NE(copy_list_element_1, original_list_element_1);
   int copy_list_element_1_value;
   ASSERT_TRUE(copy_list_element_1->GetAsInteger(&copy_list_element_1_value));
   ASSERT_EQ(1, copy_list_element_1_value);
 }
 
-TEST(ValuesTest, Equals) {
+TEST_F(ValuesTest, Equals) {
   Value* null1 = Value::CreateNullValue();
   Value* null2 = Value::CreateNullValue();
   EXPECT_NE(null1, null2);
   EXPECT_TRUE(null1->Equals(null2));
 
   Value* boolean = Value::CreateBooleanValue(false);
   EXPECT_FALSE(null1->Equals(boolean));
   delete null1;
   delete null2;
   delete boolean;
@@ skipping 17 matching lines @@
   EXPECT_FALSE(dv.Equals(copy));
   copy->Set("f", list->DeepCopy());
   EXPECT_TRUE(dv.Equals(copy));
 
   list->Append(Value::CreateBooleanValue(true));
   EXPECT_FALSE(dv.Equals(copy));
   delete copy;
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, EqualsDeprecated) {
+TEST_F(ValuesTest, EqualsDeprecated) {
   Value* null1 = Value::CreateNullValue();
   Value* null2 = Value::CreateNullValue();
   EXPECT_NE(null1, null2);
   EXPECT_TRUE(null1->Equals(null2));
 
   Value* boolean = Value::CreateBooleanValue(false);
   EXPECT_FALSE(null1->Equals(boolean));
   delete null1;
   delete null2;
   delete boolean;
@@ skipping 16 matching lines @@
 
   EXPECT_FALSE(dv.Equals(copy));
   copy->Set(L"f", list->DeepCopy());
   EXPECT_TRUE(dv.Equals(copy));
 
   list->Append(Value::CreateBooleanValue(true));
   EXPECT_FALSE(dv.Equals(copy));
   delete copy;
 }
 
-TEST(ValuesTest, RemoveEmptyChildren) {
+TEST_F(ValuesTest, RemoveEmptyChildren) {
   scoped_ptr<DictionaryValue> root(new DictionaryValue);
   // Remove empty lists and dictionaries.
   root->Set("empty_dict", new DictionaryValue);
   root->Set("empty_list", new ListValue);
   root->SetWithoutPathExpansion("a.b.c.d.e", new DictionaryValue);
   root.reset(root->DeepCopyWithoutEmptyChildren());
   EXPECT_TRUE(root->empty());
 
   // Make sure we don't prune too much.
   root->SetBoolean("bool", true);
@@ skipping 55 matching lines @@
     root.reset(root->DeepCopyWithoutEmptyChildren());
     EXPECT_EQ(3U, root->size());
     EXPECT_TRUE(root->GetList("list_with_empty_children", &inner));
     EXPECT_EQ(1U, inner->GetSize());  // Dictionary was pruned.
     EXPECT_TRUE(inner->GetList(0, &inner2));
     EXPECT_EQ(1U, inner2->GetSize());
   }
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, RemoveEmptyChildrenDeprecated) {
+TEST_F(ValuesTest, RemoveEmptyChildrenDeprecated) {
   scoped_ptr<DictionaryValue> root(new DictionaryValue);
   // Remove empty lists and dictionaries.
   root->Set(L"empty_dict", new DictionaryValue);
   root->Set(L"empty_list", new ListValue);
   root->SetWithoutPathExpansion(L"a.b.c.d.e", new DictionaryValue);
   root.reset(root->DeepCopyWithoutEmptyChildren());
   EXPECT_TRUE(root->empty());
 
   // Make sure we don't prune too much.
   root->SetBoolean(L"bool", true);
@@ skipping 54 matching lines @@
     inner2->Append(Value::CreateStringValue("hello"));
     root.reset(root->DeepCopyWithoutEmptyChildren());
     EXPECT_EQ(3U, root->size());
     EXPECT_TRUE(root->GetList(L"list_with_empty_children", &inner));
     EXPECT_EQ(1U, inner->GetSize());  // Dictionary was pruned.
     EXPECT_TRUE(inner->GetList(0, &inner2));
     EXPECT_EQ(1U, inner2->GetSize());
   }
 }
 
-TEST(ValuesTest, MergeDictionary) {
+TEST_F(ValuesTest, MergeDictionary) {
   scoped_ptr<DictionaryValue> base(new DictionaryValue);
   base->SetString("base_key", "base_key_value_base");
   base->SetString("collide_key", "collide_key_value_base");
   DictionaryValue* base_sub_dict = new DictionaryValue;
   base_sub_dict->SetString("sub_base_key", "sub_base_key_value_base");
   base_sub_dict->SetString("sub_collide_key", "sub_collide_key_value_base");
   base->Set("sub_dict_key", base_sub_dict);
 
   scoped_ptr<DictionaryValue> merge(new DictionaryValue);
   merge->SetString("merge_key", "merge_key_value_merge");
@@ skipping 25 matching lines @@
   std::string sub_collide_key_value;
   EXPECT_TRUE(res_sub_dict->GetString("sub_collide_key",
                                       &sub_collide_key_value));
   EXPECT_EQ("sub_collide_key_value_merge", sub_collide_key_value); // Replaced.
   std::string sub_merge_key_value;
   EXPECT_TRUE(res_sub_dict->GetString("sub_merge_key", &sub_merge_key_value));
   EXPECT_EQ("sub_merge_key_value_merge", sub_merge_key_value); // Merged in.
 }
 
 // TODO(viettrungluu): deprecate:
-TEST(ValuesTest, MergeDictionaryDeprecated) {
+TEST_F(ValuesTest, MergeDictionaryDeprecated) {
   scoped_ptr<DictionaryValue> base(new DictionaryValue);
   base->SetString(L"base_key", "base_key_value_base");
   base->SetString(L"collide_key", "collide_key_value_base");
   DictionaryValue* base_sub_dict = new DictionaryValue;
   base_sub_dict->SetString(L"sub_base_key", "sub_base_key_value_base");
   base_sub_dict->SetString(L"sub_collide_key", "sub_collide_key_value_base");
   base->Set(L"sub_dict_key", base_sub_dict);
 
   scoped_ptr<DictionaryValue> merge(new DictionaryValue);
   merge->SetString(L"merge_key", "merge_key_value_merge");
@@ skipping 23 matching lines @@
   EXPECT_TRUE(res_sub_dict->GetString(L"sub_base_key", &sub_base_key_value));
   EXPECT_EQ("sub_base_key_value_base", sub_base_key_value); // Preserved.
   std::string sub_collide_key_value;
   EXPECT_TRUE(res_sub_dict->GetString(L"sub_collide_key",
                                       &sub_collide_key_value));
   EXPECT_EQ("sub_collide_key_value_merge", sub_collide_key_value); // Replaced.
   std::string sub_merge_key_value;
   EXPECT_TRUE(res_sub_dict->GetString(L"sub_merge_key", &sub_merge_key_value));
   EXPECT_EQ("sub_merge_key_value_merge", sub_merge_key_value); // Merged in.
 }
+
+TEST_F(ValuesTest, GetDifferingPaths) {
+  scoped_ptr<DictionaryValue> dict1(new DictionaryValue());
+  scoped_ptr<DictionaryValue> dict2(new DictionaryValue());
+  std::vector<std::string> differing_paths;
+
+  // Test comparing empty dictionaries.
+  dict1->GetDifferingPaths(dict2.get(), &differing_paths);
+  EXPECT_EQ(differing_paths.size(), 0UL);
+
+  // Compare an empty dictionary with various non-empty dictionaries.
+  static const char* expected_paths1[] = {
+      "segment1"
+  };
+  dict1->SetString("segment1", "value1");
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths1,
+                                    arraysize(expected_paths1));
+
+  static const char* expected_paths2[] = {
+    "segment1",
+    "segment2",
+    "segment2.segment3"
+  };
+  dict1->SetString("segment2.segment3", "value2");
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths2,
+                                    arraysize(expected_paths2));
+
+  static const char* expected_paths3[] = {
+    "segment1",
+    "segment2",
+    "segment2.segment3",
+    "segment4",
+    "segment4.segment5"
+  };
+  dict1->SetString("segment4.segment5", "value3");
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths3,
+                                    arraysize(expected_paths3));
+
+  // Now various tests with two populated dictionaries.
+  static const char* expected_paths4[] = {
+    "segment1",
+    "segment2",
+    "segment2.segment3",
+    "segment4",
+    "segment4.segment5"
+  };
+  dict2->Set("segment2", new DictionaryValue());
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths4,
+                                    arraysize(expected_paths4));
+
+  static const char* expected_paths5[] = {
+    "segment1",
+    "segment4",
+    "segment4.segment5"
+  };
+  dict2->SetString("segment2.segment3", "value2");
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths5,
+                                    arraysize(expected_paths5));
+
+  dict2->SetBoolean("segment2.segment3", true);
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths4,
+                                    arraysize(expected_paths4));
+
+  // Test two identical dictionaries.
+  dict2.reset(static_cast<DictionaryValue*>(dict1->DeepCopy()));
+  dict2->GetDifferingPaths(dict1.get(), &differing_paths);
+  EXPECT_EQ(differing_paths.size(), 0UL);
+
+  // Test a deep dictionary structure.
+  static const char* expected_paths6[] = {
+    "s1",
+    "s1.s2",
+    "s1.s2.s3",
+    "s1.s2.s3.s4",
+    "s1.s2.s3.s4.s5"
+  };
+  dict1.reset(new DictionaryValue());
+  dict2.reset(new DictionaryValue());
+  dict1->Set("s1.s2.s3.s4.s5", new DictionaryValue());
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths6,
+                                    arraysize(expected_paths6));
+
+  // Make sure disjoint dictionaries generate the right differing path list.
+  static const char* expected_paths7[] = {
+    "a",
+    "b",
+    "c",
+    "d"
+  };
+  dict1.reset(new DictionaryValue());
+  dict1->SetBoolean("a", true);
+  dict1->SetBoolean("c", true);
+  dict2.reset(new DictionaryValue());
+  dict1->SetBoolean("b", true);
+  dict1->SetBoolean("d", true);
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths7,
+                                    arraysize(expected_paths7));
+
+  // For code coverage completeness. Make sure that all branches
+  // that were not covered are executed.
+  static const char* expected_paths8[] = {
+    "s1",
+    "s1.s2"
+  };
+  dict1.reset(new DictionaryValue());
+  dict1->Set("s1.s2", new DictionaryValue());
+  dict2.reset(new DictionaryValue());
+  dict2->SetInteger("s1", 1);
+  CompareDictionariesAndCheckResult(dict1.get(), dict2.get(), expected_paths8,
+                                    arraysize(expected_paths8));
+}