Fix a AppLifecycleTest present time race between the animation and the rest of the test

testing/scenario_app/ios/Scenarios/Scenarios/ScreenBeforeFlutter.h

@@ -6,8 +6,8 @@
 
 @interface ScreenBeforeFlutter : UIViewController
 
-- (id)initWithEngineRunCompletion:(void (^)(void))engineRunCompletion;
-- (FlutterViewController*)showFlutter;
+- (id)initWithEngineRunCompletion:(dispatch_block_t)engineRunCompletion;
+- (FlutterViewController*)showFlutter:(dispatch_block_t)showCompletion;
 
 @property(nonatomic, readonly) FlutterEngine* engine;
 

testing/scenario_app/ios/Scenarios/Scenarios/ScreenBeforeFlutter.m

@@ -9,7 +9,7 @@ @implementation ScreenBeforeFlutter
 
 @synthesize engine = _engine;
 
-- (id)initWithEngineRunCompletion:(void (^)(void))engineRunCompletion {
+- (id)initWithEngineRunCompletion:(dispatch_block_t)engineRunCompletion {
   self = [super init];
   _engine = [[FlutterEngine alloc] initWithScenario:@"poppable_screen"
                                      withCompletion:engineRunCompletion];
@@ -27,7 +27,7 @@ - (void)viewDidLoad {
   showFlutterButton.tintColor = UIColor.whiteColor;
   showFlutterButton.clipsToBounds = YES;
   [showFlutterButton addTarget:self
-                        action:@selector(showFlutter)
+                        action:@selector(showFlutter:)
               forControlEvents:UIControlEventTouchUpInside];
 
   [self.view addSubview:showFlutterButton];
@@ -39,11 +39,11 @@ - (void)viewDidLoad {
   [_engine runWithEntrypoint:nil];
 }
 
-- (FlutterViewController*)showFlutter {
+- (FlutterViewController*)showFlutter:(dispatch_block_t)showCompletion {
   FlutterViewController* flutterVC = [[FlutterViewController alloc] initWithEngine:_engine
                                                                            nibName:nil
                                                                             bundle:nil];
-  [self presentViewController:flutterVC animated:NO completion:nil];
+  [self presentViewController:flutterVC animated:NO completion:showCompletion];
   return flutterVC;
 }
 

testing/scenario_app/ios/Scenarios/ScenariosTests/AppLifecycleTests.m

@@ -40,17 +40,34 @@ - (void)setUp {
   self.continueAfterFailure = NO;
 }
 
-// TODO(cbracken): re-enable this test by removing the skip_ prefix once the source of its flakiness
-// has been identified. https://github.com/flutter/flutter/issues/61620
-- (void)skip_testDismissedFlutterViewControllerNotRespondingToApplicationLifecycle {
-  XCTestExpectation* engineStartedExpectation = [self expectationWithDescription:@"Engine started"];
+- (NSArray*)initialPresentLifecycles {
+  NSMutableArray* expectations =
+      [NSMutableArray arrayWithObject:[[XCAppLifecycleTestExpectation alloc]
+                                          initForLifecycle:@"AppLifecycleState.inactive"
+                                                   forStep:@"showing a FlutterViewController"]];
+
+  // If the test is the very first test to run in the test target, the UIApplication may
+  // be in inactive state. Haven't found a good way to force it to go to active state.
+  // So just account for it in the initial lifecycle events with an extra resumed since
+  // the FlutterViewController tracks all view controller and application lifecycle events.
+  if ([UIApplication sharedApplication].applicationState != UIApplicationStateActive) {
+    [expectations addObject:[[XCAppLifecycleTestExpectation alloc]
+                                initForLifecycle:@"AppLifecycleState.resumed"
+                                         forStep:@"showing a FlutterViewController"]];
+  }
+  [expectations addObject:[[XCAppLifecycleTestExpectation alloc]
+                              initForLifecycle:@"AppLifecycleState.resumed"
+                                       forStep:@"showing a FlutterViewController"]];
+  return expectations;
+}
 
+- (void)testDismissedFlutterViewControllerNotRespondingToApplicationLifecycle {
+  XCTestExpectation* engineStartedExpectation = [self expectationWithDescription:@"Engine started"];
   // Let the engine finish booting (at the end of which the channels are properly set-up) before
   // moving onto the next step of showing the next view controller.
   ScreenBeforeFlutter* rootVC = [[ScreenBeforeFlutter alloc] initWithEngineRunCompletion:^void() {
     [engineStartedExpectation fulfill];
   }];
-
   [self waitForExpectationsWithTimeout:5 handler:nil];
 
   UIApplication* application = UIApplication.sharedApplication;
@@ -60,36 +77,34 @@ - (void)skip_testDismissedFlutterViewControllerNotRespondingToApplicationLifecyc
   NSMutableArray* lifecycleExpectations = [NSMutableArray arrayWithCapacity:10];
 
   // Expected sequence from showing the FlutterViewController is inactive and resumed.
-  [lifecycleExpectations addObjectsFromArray:@[
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.inactive"
-                                                    forStep:@"showing a FlutterViewController"],
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.resumed"
-                                                    forStep:@"showing a FlutterViewController"]
-  ]];
+  [lifecycleExpectations addObjectsFromArray:[self initialPresentLifecycles]];
+
+  [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
+    if (lifecycleExpectations.count == 0) {
+      XCTFail(@"Unexpected lifecycle transition: %@", message);
+      return;
+    }
+    XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
+    if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
+      XCTFail(@"Expected lifecycle %@ but instead received %@", [nextExpectation expectedLifecycle],
+              message);
+      return;
+    }
+
+    [nextExpectation fulfill];
+    [lifecycleExpectations removeObjectAtIndex:0];
+  }];
 
   FlutterViewController* flutterVC;
   @autoreleasepool {
     // Holding onto this FlutterViewController is consequential here. Since a released
     // FlutterViewController wouldn't keep listening to the application lifecycle events and produce
     // false positives for the application lifecycle tests further below.
-    flutterVC = [rootVC showFlutter];
-    NSLog(@"FlutterViewController instance %@ created", flutterVC);
-    [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
-      if (lifecycleExpectations.count == 0) {
-        XCTFail(@"Unexpected lifecycle transition: %@", message);
-        return;
-      }
-      XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
-      if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
-        XCTFail(@"Expected lifecycle %@ but instead received %@",
-                [nextExpectation expectedLifecycle], message);
-        return;
-      }
-
-      [nextExpectation fulfill];
-      [lifecycleExpectations removeObjectAtIndex:0];
+    XCTestExpectation* vcShown = [self expectationWithDescription:@"present"];
+    flutterVC = [rootVC showFlutter:^{
+      [vcShown fulfill];
     }];
-
+    [self waitForExpectationsWithTimeout:5.0 handler:nil];
     // The expectations list isn't dequeued by the message handler yet.
     [self waitForExpectations:lifecycleExpectations timeout:5 enforceOrder:YES];
 
@@ -149,7 +164,11 @@ - (void)skip_testDismissedFlutterViewControllerNotRespondingToApplicationLifecyc
   ]];
 
   @autoreleasepool {
-    flutterVC = [rootVC showFlutter];
+    XCTestExpectation* vcShown = [self expectationWithDescription:@"present"];
+    flutterVC = [rootVC showFlutter:^{
+      [vcShown fulfill];
+    }];
+    [self waitForExpectationsWithTimeout:5.0 handler:nil];
     NSLog(@"FlutterViewController instance %@ created", flutterVC);
     [self waitForExpectations:lifecycleExpectations timeout:5 enforceOrder:YES];
 
@@ -177,9 +196,7 @@ - (void)skip_testDismissedFlutterViewControllerNotRespondingToApplicationLifecyc
   [engine destroyContext];
 }
 
-// TODO(cbracken): re-enable this test by removing the skip_ prefix once the source of its flakiness
-// has been identified. https://github.com/flutter/flutter/issues/61620
-- (void)skip_testVisibleFlutterViewControllerRespondsToApplicationLifecycle {
+- (void)testVisibleFlutterViewControllerRespondsToApplicationLifecycle {
   XCTestExpectation* engineStartedExpectation = [self expectationWithDescription:@"Engine started"];
 
   // Let the engine finish booting (at the end of which the channels are properly set-up) before
@@ -197,33 +214,31 @@ - (void)skip_testVisibleFlutterViewControllerRespondsToApplicationLifecycle {
   NSMutableArray* lifecycleExpectations = [NSMutableArray arrayWithCapacity:10];
 
   // Expected sequence from showing the FlutterViewController is inactive and resumed.
-  [lifecycleExpectations addObjectsFromArray:@[
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.inactive"
-                                                    forStep:@"showing a FlutterViewController"],
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.resumed"
-                                                    forStep:@"showing a FlutterViewController"]
-  ]];
+  [lifecycleExpectations addObjectsFromArray:[self initialPresentLifecycles]];
+
+  [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
+    if (lifecycleExpectations.count == 0) {
+      XCTFail(@"Unexpected lifecycle transition: %@", message);
+      return;
+    }
+    XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
+    if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
+      XCTFail(@"Expected lifecycle %@ but instead received %@", [nextExpectation expectedLifecycle],
+              message);
+      return;
+    }
+
+    [nextExpectation fulfill];
+    [lifecycleExpectations removeObjectAtIndex:0];
+  }];
 
   FlutterViewController* flutterVC;
   @autoreleasepool {
-    flutterVC = [rootVC showFlutter];
-    NSLog(@"FlutterViewController instance %@ created", flutterVC);
-    [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
-      if (lifecycleExpectations.count == 0) {
-        XCTFail(@"Unexpected lifecycle transition: %@", message);
-        return;
-      }
-      XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
-      if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
-        XCTFail(@"Expected lifecycle %@ but instead received %@",
-                [nextExpectation expectedLifecycle], message);
-        return;
-      }
-
-      [nextExpectation fulfill];
-      [lifecycleExpectations removeObjectAtIndex:0];
+    XCTestExpectation* vcShown = [self expectationWithDescription:@"present"];
+    flutterVC = [rootVC showFlutter:^{
+      [vcShown fulfill];
     }];
-
+    [self waitForExpectationsWithTimeout:5.0 handler:nil];
     [self waitForExpectations:lifecycleExpectations timeout:5];
 
     // Now put the FlutterViewController into background.
@@ -284,9 +299,7 @@ - (void)skip_testVisibleFlutterViewControllerRespondsToApplicationLifecycle {
   [engine destroyContext];
 }
 
-// TODO(cbracken): re-enable this test by removing the skip_ prefix once the source of its flakiness
-// has been identified. https://github.com/flutter/flutter/issues/61620
-- (void)skip_testFlutterViewControllerDetachingSendsApplicationLifecycle {
+- (void)testFlutterViewControllerDetachingSendsApplicationLifecycle {
   XCTestExpectation* engineStartedExpectation = [self expectationWithDescription:@"Engine started"];
 
   // Let the engine finish booting (at the end of which the channels are properly set-up) before
@@ -304,34 +317,33 @@ - (void)skip_testFlutterViewControllerDetachingSendsApplicationLifecycle {
   NSMutableArray* lifecycleExpectations = [NSMutableArray arrayWithCapacity:10];
 
   // Expected sequence from showing the FlutterViewController is inactive and resumed.
-  [lifecycleExpectations addObjectsFromArray:@[
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.inactive"
-                                                    forStep:@"showing a FlutterViewController"],
-    [[XCAppLifecycleTestExpectation alloc] initForLifecycle:@"AppLifecycleState.resumed"
-                                                    forStep:@"showing a FlutterViewController"]
-  ]];
+  [lifecycleExpectations addObjectsFromArray:[self initialPresentLifecycles]];
+
+  [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
+    if (lifecycleExpectations.count == 0) {
+      XCTFail(@"Unexpected lifecycle transition: %@", message);
+      return;
+    }
+    XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
+    if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
+      XCTFail(@"Expected lifecycle %@ but instead received %@", [nextExpectation expectedLifecycle],
+              message);
+      return;
+    }
+
+    [nextExpectation fulfill];
+    [lifecycleExpectations removeObjectAtIndex:0];
+  }];
+
   // At the end of Flutter VC, we want to make sure it deallocs and sends detached signal.
   // Using autoreleasepool will guarantee that.
   FlutterViewController* flutterVC;
   @autoreleasepool {
-    flutterVC = [rootVC showFlutter];
-    NSLog(@"FlutterViewController instance %@ created", flutterVC);
-    [engine.lifecycleChannel setMessageHandler:^(id message, FlutterReply callback) {
-      if (lifecycleExpectations.count == 0) {
-        XCTFail(@"Unexpected lifecycle transition: %@", message);
-        return;
-      }
-      XCAppLifecycleTestExpectation* nextExpectation = [lifecycleExpectations objectAtIndex:0];
-      if (![[nextExpectation expectedLifecycle] isEqualToString:message]) {
-        XCTFail(@"Expected lifecycle %@ but instead received %@",
-                [nextExpectation expectedLifecycle], message);
-        return;
-      }
-
-      [nextExpectation fulfill];
-      [lifecycleExpectations removeObjectAtIndex:0];
+    XCTestExpectation* vcShown = [self expectationWithDescription:@"present"];
+    flutterVC = [rootVC showFlutter:^{
+      [vcShown fulfill];
     }];
-
+    [self waitForExpectationsWithTimeout:5.0 handler:nil];
     [self waitForExpectations:lifecycleExpectations timeout:5];
 
     // Starts dealloc flutter VC.