FlutterEngineTest.java

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package test.io.flutter.embedding.engine;
 
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.any;
import static org.mockito.Mockito.anyInt;
import static org.mockito.Mockito.atLeast;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.eq;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
 
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.LocaleList;
import androidx.test.core.app.ApplicationProvider;
import androidx.test.ext.junit.runners.AndroidJUnit4;
import io.flutter.FlutterInjector;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.embedding.engine.FlutterEngine.EngineLifecycleListener;
import io.flutter.embedding.engine.FlutterEngineGroup;
import io.flutter.embedding.engine.FlutterJNI;
import io.flutter.embedding.engine.loader.FlutterLoader;
import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.embedding.engine.plugins.PluginRegistry;
import io.flutter.plugin.platform.PlatformViewsController;
import io.flutter.plugins.GeneratedPluginRegistrant;
import java.util.List;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;
import org.robolectric.Robolectric;
import org.robolectric.android.controller.ActivityController;
import org.robolectric.annotation.Config;
import org.robolectric.shadows.ShadowLog;
 
@Config(manifest = Config.NONE)
@RunWith(AndroidJUnit4.class)
public class FlutterEngineTest {
  private final Context ctx = ApplicationProvider.getApplicationContext();
  private final Context mockContext = mock(Context.class);
  @Mock FlutterJNI flutterJNI;
  boolean jniAttached;
 
  @Before
  public void setUp() {
    MockitoAnnotations.openMocks(this);
 
    Resources mockResources = mock(Resources.class);
    Configuration mockConfiguration = mock(Configuration.class);
    doReturn(mockResources).when(mockContext).getResources();
    doReturn(mockConfiguration).when(mockResources).getConfiguration();
    doReturn(LocaleList.getEmptyLocaleList()).when(mockConfiguration).getLocales();
 
    jniAttached = false;
    when(flutterJNI.isAttached()).thenAnswer(invocation -> jniAttached);
    doAnswer(
            new Answer() {
              @Override
              public Object answer(InvocationOnMock invocation) throws Throwable {
                jniAttached = true;
                return null;
              }
            })
        .when(flutterJNI)
        .attachToNative();
    GeneratedPluginRegistrant.clearRegisteredEngines();
  }
 
  @After
  public void tearDown() {
    GeneratedPluginRegistrant.clearRegisteredEngines();
    // Make sure to not forget to remove the mock exception in the generated plugin registration
    // mock, or everything subsequent will break.
    GeneratedPluginRegistrant.pluginRegistrationException = null;
  }
 
  @Test
  public void itAutomaticallyRegistersPluginsByDefault() {
    assertTrue(GeneratedPluginRegistrant.getRegisteredEngines().isEmpty());
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    when(mockFlutterLoader.automaticallyRegisterPlugins()).thenReturn(true);
    FlutterEngine flutterEngine = new FlutterEngine(ctx, mockFlutterLoader, flutterJNI);
 
    List<FlutterEngine> registeredEngines = GeneratedPluginRegistrant.getRegisteredEngines();
    assertEquals(1, registeredEngines.size());
    assertEquals(flutterEngine, registeredEngines.get(0));
  }
 
  @Test
  public void itUpdatesDisplayMetricsOnConstructionWithActivityContext() {
    // Needs an activity. ApplicationContext won't work for this.
    ActivityController<Activity> activityController = Robolectric.buildActivity(Activity.class);
    FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
    when(mockFlutterJNI.isAttached()).thenReturn(true);
 
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    FlutterEngine flutterEngine =
        new FlutterEngine(activityController.get(), mockFlutterLoader, mockFlutterJNI);
 
    verify(mockFlutterJNI, times(1))
        .updateDisplayMetrics(eq(0), any(Float.class), any(Float.class), any(Float.class));
  }
 
  @Test
  public void itSendLocalesOnEngineInit() {
    FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
    when(mockFlutterJNI.isAttached()).thenReturn(true);
 
    assertTrue(GeneratedPluginRegistrant.getRegisteredEngines().isEmpty());
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    when(mockFlutterLoader.automaticallyRegisterPlugins()).thenReturn(true);
    FlutterEngine flutterEngine = new FlutterEngine(ctx, mockFlutterLoader, mockFlutterJNI);
 
    verify(mockFlutterJNI, times(1))
        .dispatchPlatformMessage(eq("flutter/localization"), any(), anyInt(), anyInt());
  }
 
  // Helps show the root cause of MissingPluginException type errors like
  // https://github.com/flutter/flutter/issues/78625.
  @Test
  public void itCatchesAndDisplaysRegistrationExceptions() {
    assertTrue(GeneratedPluginRegistrant.getRegisteredEngines().isEmpty());
    GeneratedPluginRegistrant.pluginRegistrationException =
        new RuntimeException("I'm a bug in the plugin");
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    when(mockFlutterLoader.automaticallyRegisterPlugins()).thenReturn(true);
    FlutterEngine flutterEngine = new FlutterEngine(ctx, mockFlutterLoader, flutterJNI);
 
    List<FlutterEngine> registeredEngines = GeneratedPluginRegistrant.getRegisteredEngines();
    // When it crashes, it doesn't end up registering anything.
    assertEquals(0, registeredEngines.size());
 
    // Check the logs actually says registration failed, so a subsequent MissingPluginException
    // isn't mysterious.
    assertTrue(
        ShadowLog.getLogsForTag("GeneratedPluginsRegister")
            .get(0)
            .msg
            .contains("Tried to automatically register plugins"));
    assertEquals(
        GeneratedPluginRegistrant.pluginRegistrationException,
        ShadowLog.getLogsForTag("GeneratedPluginsRegister").get(1).throwable.getCause());
 
    GeneratedPluginRegistrant.pluginRegistrationException = null;
  }
 
  @Test
  public void itDoesNotAutomaticallyRegistersPluginsWhenFlutterLoaderDisablesIt() {
    assertTrue(GeneratedPluginRegistrant.getRegisteredEngines().isEmpty());
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    when(mockFlutterLoader.automaticallyRegisterPlugins()).thenReturn(false);
    new FlutterEngine(ctx, mockFlutterLoader, flutterJNI);
 
    List<FlutterEngine> registeredEngines = GeneratedPluginRegistrant.getRegisteredEngines();
    assertTrue(registeredEngines.isEmpty());
  }
 
  @Test
  public void itDoesNotAutomaticallyRegistersPluginsWhenFlutterEngineDisablesIt() {
    assertTrue(GeneratedPluginRegistrant.getRegisteredEngines().isEmpty());
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    when(mockFlutterLoader.automaticallyRegisterPlugins()).thenReturn(true);
    new FlutterEngine(
        ctx,
        mockFlutterLoader,
        flutterJNI,
        /*dartVmArgs=*/ new String[] {},
        /*automaticallyRegisterPlugins=*/ false);
 
    List<FlutterEngine> registeredEngines = GeneratedPluginRegistrant.getRegisteredEngines();
    assertTrue(registeredEngines.isEmpty());
  }
 
  @Test
  public void itNotifiesPlatformViewsControllerWhenDevHotRestart() {
    // Setup test.
    FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
    when(mockFlutterJNI.isAttached()).thenReturn(true);
 
    PlatformViewsController platformViewsController = mock(PlatformViewsController.class);
 
    ArgumentCaptor<FlutterEngine.EngineLifecycleListener> engineLifecycleListenerArgumentCaptor =
        ArgumentCaptor.forClass(FlutterEngine.EngineLifecycleListener.class);
 
    // Execute behavior under test.
    new FlutterEngine(
        ctx,
        mock(FlutterLoader.class),
        mockFlutterJNI,
        platformViewsController,
        /*dartVmArgs=*/ new String[] {},
        /*automaticallyRegisterPlugins=*/ false);
 
    // Obtain the EngineLifecycleListener within FlutterEngine that was given to FlutterJNI.
    verify(mockFlutterJNI)
        .addEngineLifecycleListener(engineLifecycleListenerArgumentCaptor.capture());
    FlutterEngine.EngineLifecycleListener engineLifecycleListener =
        engineLifecycleListenerArgumentCaptor.getValue();
    assertNotNull(engineLifecycleListener);
 
    // Simulate a pre-engine restart, AKA hot restart.
    engineLifecycleListener.onPreEngineRestart();
 
    // Verify that FlutterEngine notified PlatformViewsController of the pre-engine restart,
    // AKA hot restart.
    verify(platformViewsController, times(1)).onPreEngineRestart();
  }
 
  @Test
  public void itNotifiesPlatformViewsControllerAboutJNILifecycle() {
    PlatformViewsController platformViewsController = mock(PlatformViewsController.class);
 
    // Execute behavior under test.
    FlutterEngine engine =
        new FlutterEngine(
            ctx,
            mock(FlutterLoader.class),
            flutterJNI,
            platformViewsController,
            /*dartVmArgs=*/ new String[] {},
            /*automaticallyRegisterPlugins=*/ false);
    verify(platformViewsController, times(1)).onAttachedToJNI();
 
    engine.destroy();
    verify(platformViewsController, times(1)).onDetachedFromJNI();
  }
 
  @Test
  public void itUsesApplicationContext() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
 
    new FlutterEngine(
        mockContext,
        mock(FlutterLoader.class),
        flutterJNI,
        /*dartVmArgs=*/ new String[] {},
        /*automaticallyRegisterPlugins=*/ false);
 
    verify(mockContext, atLeast(1)).getApplicationContext();
  }
 
  @Test
  public void itUsesPackageContextForAssetManager() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
 
    new FlutterEngine(
        mockContext,
        mock(FlutterLoader.class),
        flutterJNI,
        /*dartVmArgs=*/ new String[] {},
        /*automaticallyRegisterPlugins=*/ false);
 
    verify(packageContext, atLeast(1)).getAssets();
    verify(mockContext, times(0)).getAssets();
  }
 
  @Test
  public void itCanUseFlutterLoaderInjectionViaFlutterInjector() throws NameNotFoundException {
    FlutterInjector.reset();
    FlutterLoader mockFlutterLoader = mock(FlutterLoader.class);
    FlutterInjector.setInstance(
        new FlutterInjector.Builder().setFlutterLoader(mockFlutterLoader).build());
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
 
    new FlutterEngine(mockContext, null, flutterJNI);
 
    verify(mockFlutterLoader, times(1)).startInitialization(any());
    verify(mockFlutterLoader, times(1)).ensureInitializationComplete(any(), any());
    FlutterInjector.reset();
  }
 
  @Test
  public void itNotifiesListenersForDestruction() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
 
    FlutterEngine engineUnderTest =
        new FlutterEngine(
            mockContext,
            mock(FlutterLoader.class),
            flutterJNI,
            /*dartVmArgs=*/ new String[] {},
            /*automaticallyRegisterPlugins=*/ false);
 
    EngineLifecycleListener listener = mock(EngineLifecycleListener.class);
    engineUnderTest.addEngineLifecycleListener(listener);
    engineUnderTest.destroy();
    verify(listener, times(1)).onEngineWillDestroy();
  }
 
  @Test
  public void itDoesNotAttachAgainWhenBuiltWithAnAttachedJNI() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
    when(flutterJNI.isAttached()).thenReturn(true);
 
    FlutterEngine engineUnderTest =
        new FlutterEngine(
            mockContext,
            mock(FlutterLoader.class),
            flutterJNI,
            /*dartVmArgs=*/ new String[] {},
            /*automaticallyRegisterPlugins=*/ false);
 
    verify(flutterJNI, never()).attachToNative();
  }
 
  @Test
  public void itComesWithARunningDartExecutorIfJNIIsAlreadyAttached() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
    when(flutterJNI.isAttached()).thenReturn(true);
 
    FlutterEngine engineUnderTest =
        new FlutterEngine(
            mockContext,
            mock(FlutterLoader.class),
            flutterJNI,
            /*dartVmArgs=*/ new String[] {},
            /*automaticallyRegisterPlugins=*/ false);
 
    assertTrue(engineUnderTest.getDartExecutor().isExecutingDart());
  }
 
  @Test
  public void passesEngineGroupToPlugins() throws NameNotFoundException {
    Context packageContext = mock(Context.class);
 
    when(mockContext.createPackageContext(any(), anyInt())).thenReturn(packageContext);
    when(flutterJNI.isAttached()).thenReturn(true);
 
    FlutterEngineGroup mockGroup = mock(FlutterEngineGroup.class);
 
    FlutterEngine engineUnderTest =
        new FlutterEngine(
            mockContext,
            mock(FlutterLoader.class),
            flutterJNI,
            new PlatformViewsController(),
            /*dartVmArgs=*/ new String[] {},
            /*automaticallyRegisterPlugins=*/ false,
            /*waitForRestorationData=*/ false,
            mockGroup);
 
    PluginRegistry registry = engineUnderTest.getPlugins();
    FlutterPlugin mockPlugin = mock(FlutterPlugin.class);
    ArgumentCaptor<FlutterPlugin.FlutterPluginBinding> pluginBindingCaptor =
        ArgumentCaptor.forClass(FlutterPlugin.FlutterPluginBinding.class);
    registry.add(mockPlugin);
    verify(mockPlugin).onAttachedToEngine(pluginBindingCaptor.capture());
    assertNotNull(pluginBindingCaptor.getValue());
    assertEquals(mockGroup, pluginBindingCaptor.getValue().getEngineGroup());
  }
}