Reland: Started waiting for the notifications locally before asserting side-effects (flutter/engine#25257)

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterEnginePlatformViewTest.mm

@@ -87,17 +87,24 @@ class MockDelegate : public PlatformView::Delegate {
   OCMVerify([mockEngine notifyLowMemory]);
   OCMReject([mockEngine notifyLowMemory]);
 
+  XCTNSNotificationExpectation* memoryExpectation = [[XCTNSNotificationExpectation alloc]
+      initWithName:UIApplicationDidReceiveMemoryWarningNotification];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationDidReceiveMemoryWarningNotification
                     object:nil];
+  [self waitForExpectations:@[ memoryExpectation ] timeout:5.0];
   OCMVerify([mockEngine notifyLowMemory]);
   OCMReject([mockEngine notifyLowMemory]);
 
+  XCTNSNotificationExpectation* backgroundExpectation = [[XCTNSNotificationExpectation alloc]
+      initWithName:UIApplicationDidEnterBackgroundNotification];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationDidEnterBackgroundNotification
                     object:nil];
+  [self waitForExpectations:@[ backgroundExpectation ] timeout:5.0];
 
   OCMVerify([mockEngine notifyLowMemory]);
+  [mockEngine stopMocking];
 }
 
 @end

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPluginAppLifeCycleDelegateTest.m

@@ -11,7 +11,6 @@
 FLUTTER_ASSERT_ARC
 
 @interface FlutterPluginAppLifeCycleDelegateTest : XCTestCase
-
 @end
 
 @implementation FlutterPluginAppLifeCycleDelegateTest
@@ -22,51 +21,71 @@ FLUTTER_ASSERT_ARC
 }
 
 - (void)testDidEnterBackground {
+  XCTNSNotificationExpectation* expectation = [[XCTNSNotificationExpectation alloc]
+      initWithName:UIApplicationDidEnterBackgroundNotification];
   FlutterPluginAppLifeCycleDelegate* delegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
   id plugin = OCMProtocolMock(@protocol(FlutterPlugin));
   [delegate addDelegate:plugin];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationDidEnterBackgroundNotification
                     object:nil];
+
+  [self waitForExpectations:@[ expectation ] timeout:5.0];
   OCMVerify([plugin applicationDidEnterBackground:[UIApplication sharedApplication]]);
 }
 
 - (void)testWillEnterForeground {
+  XCTNSNotificationExpectation* expectation = [[XCTNSNotificationExpectation alloc]
+      initWithName:UIApplicationWillEnterForegroundNotification];
+
   FlutterPluginAppLifeCycleDelegate* delegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
   id plugin = OCMProtocolMock(@protocol(FlutterPlugin));
   [delegate addDelegate:plugin];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationWillEnterForegroundNotification
                     object:nil];
+  [self waitForExpectations:@[ expectation ] timeout:5.0];
   OCMVerify([plugin applicationWillEnterForeground:[UIApplication sharedApplication]]);
 }
 
-- (void)skip_testWillResignActive {
+- (void)testWillResignActive {
+  XCTNSNotificationExpectation* expectation =
+      [[XCTNSNotificationExpectation alloc] initWithName:UIApplicationWillResignActiveNotification];
+
   FlutterPluginAppLifeCycleDelegate* delegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
   id plugin = OCMProtocolMock(@protocol(FlutterPlugin));
   [delegate addDelegate:plugin];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationWillResignActiveNotification
                     object:nil];
+  [self waitForExpectations:@[ expectation ] timeout:5.0];
   OCMVerify([plugin applicationWillResignActive:[UIApplication sharedApplication]]);
 }
 
-- (void)skip_testDidBecomeActive {
+- (void)testDidBecomeActive {
+  XCTNSNotificationExpectation* expectation =
+      [[XCTNSNotificationExpectation alloc] initWithName:UIApplicationDidBecomeActiveNotification];
+
   FlutterPluginAppLifeCycleDelegate* delegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
   id plugin = OCMProtocolMock(@protocol(FlutterPlugin));
   [delegate addDelegate:plugin];
   [[NSNotificationCenter defaultCenter]
       postNotificationName:UIApplicationDidBecomeActiveNotification
                     object:nil];
+  [self waitForExpectations:@[ expectation ] timeout:5.0];
   OCMVerify([plugin applicationDidBecomeActive:[UIApplication sharedApplication]]);
 }
 
 - (void)testWillTerminate {
+  XCTNSNotificationExpectation* expectation =
+      [[XCTNSNotificationExpectation alloc] initWithName:UIApplicationWillTerminateNotification];
+
   FlutterPluginAppLifeCycleDelegate* delegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
   id plugin = OCMProtocolMock(@protocol(FlutterPlugin));
   [delegate addDelegate:plugin];
   [[NSNotificationCenter defaultCenter] postNotificationName:UIApplicationWillTerminateNotification
                                                       object:nil];
+  [self waitForExpectations:@[ expectation ] timeout:5.0];
   OCMVerify([plugin applicationWillTerminate:[UIApplication sharedApplication]]);
 }
 

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterTextInputPluginTest.m

@@ -885,9 +885,8 @@ FLUTTER_ASSERT_ARC
 
 - (void)testFlutterTextInputPluginRetainsFlutterTextInputView {
   FlutterTextInputPlugin* myInputPlugin;
-  id myEngine = OCMClassMock([FlutterEngine class]);
   myInputPlugin = [[FlutterTextInputPlugin alloc] init];
-  myInputPlugin.textInputDelegate = myEngine;
+  myInputPlugin.textInputDelegate = engine;
   __weak UIView* activeView;
   @autoreleasepool {
     FlutterMethodCall* setClientCall = [FlutterMethodCall

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterViewControllerTest.mm

@@ -16,6 +16,22 @@ namespace flutter {
 class PointerDataPacket {};
 }
 
+/// Sometimes we have to use a custom mock to avoid retain cycles in ocmock.
+@interface FlutterEnginePartialMock : FlutterEngine
+@property(nonatomic, strong) FlutterBasicMessageChannel* lifecycleChannel;
+@property(nonatomic, weak) FlutterViewController* viewController;
+@property(nonatomic, assign) BOOL didCallNotifyLowMemory;
+@end
+
+@implementation FlutterEnginePartialMock
+@synthesize viewController;
+@synthesize lifecycleChannel;
+
+- (void)notifyLowMemory {
+  _didCallNotifyLowMemory = YES;
+}
+@end
+
 @interface FlutterEngine ()
 - (BOOL)createShell:(NSString*)entrypoint
          libraryURI:(NSString*)libraryURI
@@ -87,14 +103,15 @@ typedef enum UIAccessibilityContrast : NSInteger {
 
 - (void)testViewDidDisappearDoesntPauseEngineWhenNotTheViewController {
   id lifecycleChannel = OCMClassMock([FlutterBasicMessageChannel class]);
-  OCMStub([self.mockEngine lifecycleChannel]).andReturn(lifecycleChannel);
+  FlutterEnginePartialMock* mockEngine = [[FlutterEnginePartialMock alloc] init];
+  mockEngine.lifecycleChannel = lifecycleChannel;
   FlutterViewController* viewControllerA =
       [[FlutterViewController alloc] initWithEngine:self.mockEngine nibName:nil bundle:nil];
   FlutterViewController* viewControllerB =
       [[FlutterViewController alloc] initWithEngine:self.mockEngine nibName:nil bundle:nil];
   id viewControllerMock = OCMPartialMock(viewControllerA);
   OCMStub([viewControllerMock surfaceUpdated:NO]);
-  OCMStub([self.mockEngine viewController]).andReturn(viewControllerB);
+  mockEngine.viewController = viewControllerB;
   [viewControllerA viewDidDisappear:NO];
   OCMReject([lifecycleChannel sendMessage:@"AppLifecycleState.paused"]);
   OCMReject([viewControllerMock surfaceUpdated:[OCMArg any]]);
@@ -102,15 +119,21 @@ typedef enum UIAccessibilityContrast : NSInteger {
 
 - (void)testViewDidDisappearDoesPauseEngineWhenIsTheViewController {
   id lifecycleChannel = OCMClassMock([FlutterBasicMessageChannel class]);
-  OCMStub([self.mockEngine lifecycleChannel]).andReturn(lifecycleChannel);
-  FlutterViewController* viewController =
-      [[FlutterViewController alloc] initWithEngine:self.mockEngine nibName:nil bundle:nil];
-  id viewControllerMock = OCMPartialMock(viewController);
-  OCMStub([viewControllerMock surfaceUpdated:NO]);
-  OCMStub([self.mockEngine viewController]).andReturn(viewController);
-  [viewController viewDidDisappear:NO];
-  OCMVerify([lifecycleChannel sendMessage:@"AppLifecycleState.paused"]);
-  OCMVerify([viewControllerMock surfaceUpdated:NO]);
+  FlutterEnginePartialMock* mockEngine = [[FlutterEnginePartialMock alloc] init];
+  mockEngine.lifecycleChannel = lifecycleChannel;
+  __weak FlutterViewController* weakViewController;
+  @autoreleasepool {
+    FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:mockEngine
+                                                                                  nibName:nil
+                                                                                   bundle:nil];
+    weakViewController = viewController;
+    id viewControllerMock = OCMPartialMock(viewController);
+    OCMStub([viewControllerMock surfaceUpdated:NO]);
+    [viewController viewDidDisappear:NO];
+    OCMVerify([lifecycleChannel sendMessage:@"AppLifecycleState.paused"]);
+    OCMVerify([viewControllerMock surfaceUpdated:NO]);
+  }
+  XCTAssertNil(weakViewController);
 }
 
 - (void)testBinaryMessenger {
@@ -528,15 +551,16 @@ typedef enum UIAccessibilityContrast : NSInteger {
 }
 
 - (void)testNotifyLowMemory {
-  FlutterViewController* viewController =
-      [[FlutterViewController alloc] initWithEngine:self.mockEngine nibName:nil bundle:nil];
-  OCMStub([self.mockEngine viewController]).andReturn(viewController);
+  FlutterEnginePartialMock* mockEngine = [[FlutterEnginePartialMock alloc] init];
+  FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:mockEngine
+                                                                                nibName:nil
+                                                                                 bundle:nil];
   id viewControllerMock = OCMPartialMock(viewController);
   OCMStub([viewControllerMock surfaceUpdated:NO]);
-
   [viewController beginAppearanceTransition:NO animated:NO];
   [viewController endAppearanceTransition];
-  OCMVerify([self.mockEngine notifyLowMemory]);
+  XCTAssertTrue(mockEngine.didCallNotifyLowMemory);
+  [viewControllerMock stopMocking];
 }
 
 - (void)testValidKeyUpEvent API_AVAILABLE(ios(13.4)) {

engine/src/flutter/shell/platform/darwin/ios/framework/Source/accessibility_bridge_test.mm

@@ -970,5 +970,6 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
   });
   latch.Wait();
   OCMVerify([messenger cleanupConnection:connection]);
+  [engine stopMocking];
 }
 @end