[Dark] Add unit test for GlobalNightModeStateController

Bug: 948443
Change-Id: I2fe90e283fad46f5d2fecc71abd61392074c9af7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1601933
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659214}

chrome/android/chrome_java_sources.gni

@@ -882,6 +882,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/nfc/BeamController.java",
   "java/src/org/chromium/chrome/browser/nfc/BeamProvider.java",
   "java/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateController.java",
+  "java/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateProviderHolder.java",
   "java/src/org/chromium/chrome/browser/night_mode/NightModeMetrics.java",
   "java/src/org/chromium/chrome/browser/night_mode/NightModeStateProvider.java",
   "java/src/org/chromium/chrome/browser/night_mode/NightModeUtils.java",

chrome/android/chrome_junit_test_java_sources.gni

@@ -113,6 +113,8 @@ chrome_junit_test_java_sources = [
   "junit/src/org/chromium/chrome/browser/notifications/NotificationTriggerBackgroundTaskTest.java",
   "junit/src/org/chromium/chrome/browser/notifications/NotificationTriggerSchedulerTest.java",
   "junit/src/org/chromium/chrome/browser/notifications/channels/ChannelDefinitionsTest.java",
+  "junit/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateControllerTest.java",
+  "junit/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateProviderHolderTest.java",
   "junit/src/org/chromium/chrome/browser/ntp/TitleUtilTest.java",
   "junit/src/org/chromium/chrome/browser/ntp/cards/ContentSuggestionsUnitTestUtils.java",
   "junit/src/org/chromium/chrome/browser/ntp/cards/InnerNodeTest.java",

chrome/android/java/src/org/chromium/chrome/browser/ChromeBaseAppCompatActivity.java

@@ -12,7 +12,7 @@ import android.support.annotation.Nullable;
 import android.support.annotation.StyleRes;
 import android.support.v7.app.AppCompatActivity;
 
-import org.chromium.chrome.browser.night_mode.GlobalNightModeStateController;
+import org.chromium.chrome.browser.night_mode.GlobalNightModeStateProviderHolder;
 import org.chromium.chrome.browser.night_mode.NightModeStateProvider;
 import org.chromium.chrome.browser.night_mode.NightModeUtils;
 
@@ -90,7 +90,7 @@ public class ChromeBaseAppCompatActivity
      *         of this class.
      */
     protected NightModeStateProvider createNightModeStateProvider() {
-        return GlobalNightModeStateController.getInstance();
+        return GlobalNightModeStateProviderHolder.getInstance();
     }
 
     /**

chrome/android/java/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateController.java

@@ -22,20 +22,18 @@ import org.chromium.base.ApplicationState;
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.ObserverList;
-import org.chromium.chrome.browser.ChromeBaseAppCompatActivity;
 import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
 import org.chromium.chrome.browser.preferences.themes.ThemePreferences;
-import org.chromium.chrome.browser.util.FeatureUtilities;
 
 /**
  * Maintains and provides the night mode state for the entire application.
  */
-public class GlobalNightModeStateController implements NightModeStateProvider,
+class GlobalNightModeStateController implements NightModeStateProvider,
                                                 SystemNightModeMonitor.Observer,
                                                 ApplicationStatus.ApplicationStateListener {
-    private static GlobalNightModeStateController sInstance;
-
     private final ObserverList<Observer> mObservers = new ObserverList<>();
+    private final SystemNightModeMonitor mSystemNightModeMonitor;
+    private final ChromePreferenceManager mChromePreferenceManager;
 
     /**
      * Whether night mode is enabled throughout the entire app. If null, night mode is not
@@ -53,24 +51,17 @@ public class GlobalNightModeStateController implements NightModeStateProvider,
     private boolean mIsStarted;
 
     /**
-     * @return The {@link GlobalNightModeStateController} that maintains the night mode state for
-     *         the entire application. Note that UI widgets should always get the
-     *         {@link NightModeStateProvider} from the {@link ChromeBaseAppCompatActivity} they are
-     *         attached to, because the night mode state can be overridden at the activity level.
+     * Should not directly instantiate unless for testing purpose. Use
+     * {@link GlobalNightModeStateProviderHolder#getInstance()} instead.
+     * @param systemNightModeMonitor The {@link SystemNightModeMonitor} that maintains the system
+     *                               night mode state.
+     * @param chromePreferenceManager The {@link ChromePreferenceManager} that maintains shared
+     *                                preferences.
      */
-    public static GlobalNightModeStateController getInstance() {
-        if (sInstance == null) {
-            sInstance = new GlobalNightModeStateController();
-        }
-        return sInstance;
-    }
-
-    private GlobalNightModeStateController() {
-        if (!NightModeUtils.isNightModeSupported() || !FeatureUtilities.isNightModeAvailable()) {
-            // Always stay in light mode if night mode is not available.
-            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
-            return;
-        }
+    GlobalNightModeStateController(@NonNull SystemNightModeMonitor systemNightModeMonitor,
+            @NonNull ChromePreferenceManager chromePreferenceManager) {
+        mSystemNightModeMonitor = systemNightModeMonitor;
+        mChromePreferenceManager = chromePreferenceManager;
 
         mPreferenceObserver = key -> {
             if (TextUtils.equals(key, UI_THEME_SETTING_KEY)) updateNightMode();
@@ -131,8 +122,8 @@ public class GlobalNightModeStateController implements NightModeStateProvider,
             ContextUtils.getApplicationContext().registerReceiver(mPowerModeReceiver,
                     new IntentFilter(PowerManager.ACTION_POWER_SAVE_MODE_CHANGED));
         }
-        SystemNightModeMonitor.getInstance().addObserver(this);
-        ChromePreferenceManager.getInstance().addObserver(mPreferenceObserver);
+        mSystemNightModeMonitor.addObserver(this);
+        mChromePreferenceManager.addObserver(mPreferenceObserver);
         updateNightMode();
     }
 
@@ -144,16 +135,14 @@ public class GlobalNightModeStateController implements NightModeStateProvider,
         if (mPowerModeReceiver != null) {
             ContextUtils.getApplicationContext().unregisterReceiver(mPowerModeReceiver);
         }
-        SystemNightModeMonitor.getInstance().removeObserver(this);
-        ChromePreferenceManager.getInstance().removeObserver(mPreferenceObserver);
+        mSystemNightModeMonitor.removeObserver(this);
+        mChromePreferenceManager.removeObserver(mPreferenceObserver);
     }
 
     private void updateNightMode() {
-        final int themeSetting =
-                ChromePreferenceManager.getInstance().readInt(UI_THEME_SETTING_KEY);
+        final int themeSetting = mChromePreferenceManager.readInt(UI_THEME_SETTING_KEY);
         final boolean newNightModeOn = themeSetting == ThemePreferences.ThemeSetting.SYSTEM_DEFAULT
-                        && (mPowerSaveModeOn
-                                || SystemNightModeMonitor.getInstance().isSystemNightModeOn())
+                        && (mPowerSaveModeOn || mSystemNightModeMonitor.isSystemNightModeOn())
                 || themeSetting == ThemePreferences.ThemeSetting.DARK;
         if (mNightModeOn != null && newNightModeOn == mNightModeOn) return;
 

chrome/android/java/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateProviderHolder.java

+// Copyright 2019 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.
+
+package org.chromium.chrome.browser.night_mode;
+
+import android.support.annotation.NonNull;
+import android.support.v7.app.AppCompatDelegate;
+
+import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.browser.ChromeBaseAppCompatActivity;
+import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
+import org.chromium.chrome.browser.util.FeatureUtilities;
+
+/**
+ * Holds an instance of {@link NightModeStateProvider} that provides night mode state for the entire
+ * application.
+ */
+public class GlobalNightModeStateProviderHolder {
+    private static NightModeStateProvider sInstance;
+
+    /**
+     * Created when night mode is not available or not supported.
+     */
+    private static class DummyNightModeStateProvider implements NightModeStateProvider {
+        private DummyNightModeStateProvider() {
+            // Always stay in light mode if night mode is not available.
+            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
+        }
+
+        @Override
+        public boolean isInNightMode() {
+            return false;
+        }
+
+        @Override
+        public void addObserver(@NonNull Observer observer) {}
+
+        @Override
+        public void removeObserver(@NonNull Observer observer) {}
+    }
+
+    /**
+     * @return The {@link NightModeStateProvider} that maintains the night mode state for the entire
+     *         application. Note that UI widgets should always get the
+     *         {@link NightModeStateProvider} from the {@link ChromeBaseAppCompatActivity} they are
+     *         attached to, because the night mode state can be overridden at the activity level.
+     */
+    public static NightModeStateProvider getInstance() {
+        if (sInstance == null) {
+            if (!NightModeUtils.isNightModeSupported()
+                    || !FeatureUtilities.isNightModeAvailable()) {
+                sInstance = new DummyNightModeStateProvider();
+            } else {
+                sInstance = new GlobalNightModeStateController(SystemNightModeMonitor.getInstance(),
+                        ChromePreferenceManager.getInstance());
+            }
+        }
+        return sInstance;
+    }
+
+    @VisibleForTesting
+    static void resetInstanceForTesting() {
+        sInstance = null;
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/night_mode/SystemNightModeMonitor.java

@@ -8,6 +8,7 @@ import android.content.res.Configuration;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.ObserverList;
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.ChromeApplication;
 
 /**
@@ -76,4 +77,9 @@ public class SystemNightModeMonitor {
         mSystemNightModeOn =
                 (uiMode & Configuration.UI_MODE_NIGHT_MASK) == Configuration.UI_MODE_NIGHT_YES;
     }
+
+    @VisibleForTesting
+    void notifyObserversForTesting() {
+        for (Observer observer : mObservers) observer.onSystemNightModeChanged();
+    }
 }

chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java

@@ -14,6 +14,7 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.UserManager;
 import android.speech.RecognizerIntent;
+import android.support.annotation.Nullable;
 
 import org.chromium.base.CommandLine;
 import org.chromium.base.ContextUtils;
@@ -535,6 +536,15 @@ public class FeatureUtilities {
         return sIsNightModeAvailable;
     }
 
+    /**
+     * Toggles whether the night mode experiment is enabled for testing. Should be reset back to
+     * null after the test has finished.
+     */
+    @VisibleForTesting
+    public static void setNightModeAvailableForTesting(@Nullable Boolean available) {
+        sIsNightModeAvailable = available;
+    }
+
     /**
      * Cache whether or not night mode is available for custom tabs (i.e. night mode experiment is
      * enabled), so the value is immediately available on next start-up.

chrome/android/junit/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateControllerTest.java

+// Copyright 2019 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.
+
+package org.chromium.chrome.browser.night_mode;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+import static org.robolectric.Shadows.shadowOf;
+
+import static org.chromium.base.ApplicationState.HAS_RUNNING_ACTIVITIES;
+import static org.chromium.base.ApplicationState.HAS_STOPPED_ACTIVITIES;
+import static org.chromium.chrome.browser.preferences.ChromePreferenceManager.UI_THEME_SETTING_KEY;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.PowerManager;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+import org.robolectric.shadows.ShadowPowerManager;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
+import org.chromium.chrome.browser.preferences.themes.ThemePreferences;
+
+/**
+ * Unit tests for {@link GlobalNightModeStateController}.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class GlobalNightModeStateControllerTest {
+    @Mock
+    private NightModeStateProvider.Observer mObserver;
+
+    private GlobalNightModeStateController mGlobalNightModeStateController;
+
+    private SystemNightModeMonitor mSystemNightModeMonitor;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+
+        mSystemNightModeMonitor = spy(SystemNightModeMonitor.getInstance());
+        mGlobalNightModeStateController = new GlobalNightModeStateController(
+                mSystemNightModeMonitor, ChromePreferenceManager.getInstance());
+
+        mGlobalNightModeStateController.onApplicationStateChange(HAS_RUNNING_ACTIVITIES);
+
+        // Night mode is disabled by default.
+        assertFalse(GlobalNightModeStateProviderHolder.getInstance().isInNightMode());
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        ChromePreferenceManager.getInstance().removeKey(UI_THEME_SETTING_KEY);
+    }
+
+    @Test
+    public void testUpdateNightMode_PowerSaveMode() {
+        // Enable power save mode and verify night mode is enabled.
+        setIsPowerSaveMode(true);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        // Disable power save mode and verify night mode is disabled.
+        setIsPowerSaveMode(false);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+    }
+
+    @Test
+    public void testUpdateNightMode_SystemNightMode() {
+        // Enable system night mode and verify night mode is enabled.
+        setSystemNightMode(true);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        // Disable system night mode and verify night mode is disabled.
+        setSystemNightMode(false);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+    }
+
+    @Test
+    public void testUpdateNightMode_Preference() {
+        // Set preference to dark theme and verify night mode is enabled.
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.DARK);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        // Set preference to light theme and verify night mode is disabled.
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.LIGHT);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
+        // Regardless of power save mode and system night mode, night mode is disabled with light
+        // theme preference.
+        setIsPowerSaveMode(true);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
+        setSystemNightMode(true);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+    }
+
+    @Test
+    public void testStopAndRestart() {
+        // Simulate to stop listening to night mode state changes. Verify that night mode state is
+        // not changed.
+        mGlobalNightModeStateController.onApplicationStateChange(HAS_STOPPED_ACTIVITIES);
+        setIsPowerSaveMode(true);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
+        setSystemNightMode(true);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.DARK);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
+        // Simulate to start listening to night mode state changes. Verify that
+        //   1. Night mode state is updated after #start().
+        //   2. Night mode state is updated on power save mode, system night mode, or preference
+        //      changes.
+        mGlobalNightModeStateController.onApplicationStateChange(HAS_RUNNING_ACTIVITIES);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.SYSTEM_DEFAULT);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        setIsPowerSaveMode(false);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+
+        setSystemNightMode(false);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+    }
+
+    @Test
+    public void testObserver() {
+        mGlobalNightModeStateController.addObserver(mObserver);
+
+        // Verify that observer is called on night mode state changed from false to true.
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.DARK);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+        verify(mObserver, times(1)).onNightModeStateChanged();
+
+        // Verify that observer is not called when night mode state is not changed.
+        setIsPowerSaveMode(true);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+        verify(mObserver, times(1)).onNightModeStateChanged();
+
+        // Verify that observer is not called when night mode state is not changed.
+        setIsPowerSaveMode(false);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+        verify(mObserver, times(1)).onNightModeStateChanged();
+
+        // Verify that observer is called when set to light theme.
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.LIGHT);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+        verify(mObserver, times(2)).onNightModeStateChanged();
+
+        // Verify that observer is not called after it is removed.
+        mGlobalNightModeStateController.removeObserver(mObserver);
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.DARK);
+        assertTrue(mGlobalNightModeStateController.isInNightMode());
+        verify(mObserver, times(2)).onNightModeStateChanged();
+    }
+
+    /**
+     * Simulates setting power save mode, and notifies the change.
+     * @param isPowerSaveMode Whether power save mode is enabled or not.
+     */
+    private void setIsPowerSaveMode(boolean isPowerSaveMode) {
+        PowerManager powerManager = (PowerManager) RuntimeEnvironment.application.getSystemService(
+                Context.POWER_SERVICE);
+        ShadowPowerManager shadowPowerManager = shadowOf(powerManager);
+        shadowPowerManager.setIsPowerSaveMode(isPowerSaveMode);
+        ContextUtils.getApplicationContext().sendBroadcast(
+                new Intent(PowerManager.ACTION_POWER_SAVE_MODE_CHANGED));
+    }
+
+    /**
+     * Simulates setting system night mode, and notifies the change.
+     * @param isSystemNightModeOn Whether system night mode is enabled or not.
+     */
+    private void setSystemNightMode(boolean isSystemNightModeOn) {
+        when(mSystemNightModeMonitor.isSystemNightModeOn()).thenReturn(isSystemNightModeOn);
+        mSystemNightModeMonitor.notifyObserversForTesting();
+    }
+}

chrome/android/junit/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateProviderHolderTest.java

+// Copyright 2019 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.
+
+package org.chromium.chrome.browser.night_mode;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import static org.chromium.chrome.browser.preferences.ChromePreferenceManager.UI_THEME_SETTING_KEY;
+
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
+import org.chromium.chrome.browser.preferences.themes.ThemePreferences;
+import org.chromium.chrome.browser.util.FeatureUtilities;
+
+/**
+ * Unit tests for {@link GlobalNightModeStateProviderHolder}.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class GlobalNightModeStateProviderHolderTest {
+    @After
+    public void tearDown() throws Exception {
+        FeatureUtilities.setNightModeAvailableForTesting(null);
+        GlobalNightModeStateProviderHolder.resetInstanceForTesting();
+        ChromePreferenceManager.getInstance().removeKey(UI_THEME_SETTING_KEY);
+    }
+
+    @Test
+    public void testNightModeNotAvailable() {
+        FeatureUtilities.setNightModeAvailableForTesting(false);
+
+        // Verify that night mode is disabled.
+        assertFalse(GlobalNightModeStateProviderHolder.getInstance().isInNightMode());
+
+        // Verify that night mode cannot be enabled.
+        ChromePreferenceManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.DARK);
+        assertFalse(GlobalNightModeStateProviderHolder.getInstance().isInNightMode());
+    }
+
+    @Test
+    public void testNightModeAvailable() {
+        // Verify that the instance is a GlobalNightModeStateController. Other tests are covered
+        // in GlobalNightModeStateControllerTest.java.
+        FeatureUtilities.setNightModeAvailableForTesting(true);
+        assertTrue(GlobalNightModeStateProviderHolder.getInstance()
+                           instanceof GlobalNightModeStateController);
+    }
+}