Upstream Chrome on iOS source code [8/11].

ios/chrome/browser/ui/settings/utils/pref_backed_boolean_unittest.mm

+// Copyright 2016 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.
+
+#import "ios/chrome/browser/ui/settings/utils/pref_backed_boolean.h"
+
+#include "base/mac/scoped_nsobject.h"
+#include "base/values.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/testing_pref_service.h"
+#import "ios/chrome/browser/ui/settings/utils/fake_observable_boolean.h"
+#include "ios/web/public/test/test_web_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+namespace {
+
+const char kTestSwitchPref[] = "test-pref";
+
+class PrefBackedBooleanTest : public PlatformTest {
+ public:
+  void SetUp() override {
+    pref_service_.registry()->RegisterBooleanPref(kTestSwitchPref, false);
+    observable_boolean_.reset([[PrefBackedBoolean alloc]
+        initWithPrefService:&pref_service_
+                   prefName:kTestSwitchPref]);
+  }
+
+ protected:
+  bool GetPref() { return pref_service_.GetBoolean(kTestSwitchPref); }
+
+  void SetPref(bool value) {
+    base::Value* booleanValue = new base::FundamentalValue(value);
+    pref_service_.SetUserPref(kTestSwitchPref, booleanValue);
+  }
+
+  PrefBackedBoolean* GetObservableBoolean() {
+    return observable_boolean_.get();
+  }
+
+  web::TestWebThreadBundle thread_bundle_;
+  TestingPrefServiceSimple pref_service_;
+  base::scoped_nsobject<PrefBackedBoolean> observable_boolean_;
+};
+
+TEST_F(PrefBackedBooleanTest, ReadFromPrefs) {
+  SetPref(false);
+  EXPECT_FALSE(GetObservableBoolean().value);
+
+  SetPref(true);
+  EXPECT_TRUE(GetObservableBoolean().value);
+}
+
+TEST_F(PrefBackedBooleanTest, WriteToPrefs) {
+  GetObservableBoolean().value = true;
+  EXPECT_TRUE(GetPref());
+
+  GetObservableBoolean().value = false;
+  EXPECT_FALSE(GetPref());
+}
+
+TEST_F(PrefBackedBooleanTest, ObserverUpdates) {
+  SetPref(false);
+  base::scoped_nsobject<TestBooleanObserver> observer(
+      [[TestBooleanObserver alloc] init]);
+  GetObservableBoolean().observer = observer;
+  EXPECT_EQ(0, observer.get().updateCount);
+
+  SetPref(true);
+  EXPECT_EQ(1, observer.get().updateCount)
+      << "Changing value should update observer";
+
+  SetPref(true);
+  EXPECT_EQ(1, observer.get().updateCount)
+      << "Setting the same value should not update observer";
+}
+
+}  // namespace