Clean up pref change notification handling.

chrome/browser/prefs/pref_notifier_impl_unittest.cc

Index: chrome/browser/prefs/pref_notifier_impl_unittest.cc
diff --git a/chrome/browser/prefs/pref_notifier_impl_unittest.cc b/chrome/browser/prefs/pref_notifier_impl_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8f3be3c33c0e852d739e477d0d9ce95510d2a11a
--- /dev/null
+++ b/chrome/browser/prefs/pref_notifier_impl_unittest.cc
@@ -0,0 +1,199 @@
+// 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 "chrome/browser/prefs/pref_notifier_impl.h"
+#include "chrome/browser/prefs/pref_observer_mock.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/prefs/pref_value_store.h"
+#include "chrome/common/notification_observer_mock.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/test/testing_pref_service.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::_;
+using testing::Field;
+using testing::Invoke;
+using testing::Mock;
+using testing::Truly;
+
+namespace {
+
+const char kChangedPref[] = "changed_pref";
+const char kUnchangedPref[] = "unchanged_pref";
+
+bool DetailsAreChangedPref(const Details<std::string>& details) {
+  std::string* string_in = Details<std::string>(details).ptr();
+  return strcmp(string_in->c_str(), kChangedPref) == 0;
+}
+
+// Test PrefNotifier that allows tracking of observers and notifications.
+class MockPrefNotifier : public PrefNotifierImpl {
+ public:
+  explicit MockPrefNotifier(PrefService* pref_service)
+      : PrefNotifierImpl(pref_service) {}
+  virtual ~MockPrefNotifier() {}
+
+  MOCK_METHOD1(FireObservers, void(const std::string& path));
+
+  size_t CountObserver(const char* path, NotificationObserver* obs) {
+    PrefObserverMap::const_iterator observer_iterator =
+        pref_observers()->find(path);
+    if (observer_iterator == pref_observers()->end())
+      return false;
+
+    NotificationObserverList* observer_list = observer_iterator->second;
+    NotificationObserverList::Iterator it(*observer_list);
+    NotificationObserver* existing_obs;
+    size_t count = 0;
+    while ((existing_obs = it.GetNext()) != NULL) {
+      if (existing_obs == obs)
+        count++;
+    }
+
+    return count;
+  }
+};
+
+// Test fixture class.
+class PrefNotifierTest : public testing::Test {
+ protected:
+  virtual void SetUp() {
+    pref_service_.RegisterBooleanPref(kChangedPref, true);
+    pref_service_.RegisterBooleanPref(kUnchangedPref, true);
+  }
+
+  TestingPrefService pref_service_;
+
+  PrefObserverMock obs1_;
+  PrefObserverMock obs2_;
+};
+
+TEST_F(PrefNotifierTest, OnPreferenceChanged) {
+  MockPrefNotifier notifier(&pref_service_);
+  EXPECT_CALL(notifier, FireObservers(kChangedPref)).Times(1);
+  notifier.OnPreferenceChanged(kChangedPref);
+}
+
+TEST_F(PrefNotifierTest, OnInitializationCompleted) {
+  MockPrefNotifier notifier(&pref_service_);
+  NotificationObserverMock observer;
+  NotificationRegistrar registrar;
+  registrar.Add(&observer, NotificationType::PREF_INITIALIZATION_COMPLETED,
+                Source<PrefService>(&pref_service_));
+  EXPECT_CALL(observer, Observe(
+      Field(&NotificationType::value,
+            NotificationType::PREF_INITIALIZATION_COMPLETED),
+      Source<PrefService>(&pref_service_),
+      NotificationService::NoDetails()));
+  notifier.OnInitializationCompleted();
+}
+
+TEST_F(PrefNotifierTest, AddAndRemovePrefObservers) {
+  const char pref_name[] = "homepage";
+  const char pref_name2[] = "proxy";
+
+  MockPrefNotifier notifier(&pref_service_);
+  notifier.AddPrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Re-adding the same observer for the same pref doesn't change anything.
+  // Skip this in debug mode, since it hits a DCHECK and death tests aren't
+  // thread-safe.
+#if defined(NDEBUG)
+  notifier.AddPrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+#endif  // NDEBUG
+
+  // Ensure that we can add the same observer to a different pref.
+  notifier.AddPrefObserver(pref_name2, &obs1_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Ensure that we can add another observer to the same pref.
+  notifier.AddPrefObserver(pref_name, &obs2_);
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  // Ensure that we can remove all observers, and that removing a non-existent
+  // observer is harmless.
+  notifier.RemovePrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name, &obs2_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(1u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+
+  notifier.RemovePrefObserver(pref_name2, &obs1_);
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs1_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name, &obs2_));
+  ASSERT_EQ(0u, notifier.CountObserver(pref_name2, &obs2_));
+}
+
+TEST_F(PrefNotifierTest, FireObservers) {
+  FundamentalValue value_true(true);
+  PrefNotifierImpl notifier(&pref_service_);
+  notifier.AddPrefObserver(kChangedPref, &obs1_);
+  notifier.AddPrefObserver(kUnchangedPref, &obs1_);
+
+  obs1_.Expect(&pref_service_, kChangedPref, &value_true);
+  EXPECT_CALL(obs2_, Observe(_, _, _)).Times(0);
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  notifier.AddPrefObserver(kChangedPref, &obs2_);
+  notifier.AddPrefObserver(kUnchangedPref, &obs2_);
+
+  obs1_.Expect(&pref_service_, kChangedPref, &value_true);
+  obs2_.Expect(&pref_service_, kChangedPref, &value_true);
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  // Make sure removing an observer from one pref doesn't affect anything else.
+  notifier.RemovePrefObserver(kChangedPref, &obs1_);
+
+  EXPECT_CALL(obs1_, Observe(_, _, _)).Times(0);
+  obs2_.Expect(&pref_service_, kChangedPref, &value_true);
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  // Make sure removing an observer entirely doesn't affect anything else.
+  notifier.RemovePrefObserver(kUnchangedPref, &obs1_);
+
+  EXPECT_CALL(obs1_, Observe(_, _, _)).Times(0);
+  obs2_.Expect(&pref_service_, kChangedPref, &value_true);
+  notifier.OnPreferenceChanged(kChangedPref);
+  Mock::VerifyAndClearExpectations(&obs1_);
+  Mock::VerifyAndClearExpectations(&obs2_);
+
+  notifier.RemovePrefObserver(kChangedPref, &obs2_);
+  notifier.RemovePrefObserver(kUnchangedPref, &obs2_);
+}
+
+}  // namespace