[webview_flutter] Maybe fix flakiness of integration tests

packages/webview_flutter/webview_flutter/example/integration_test/webview_flutter_test.dart

@@ -23,8 +23,6 @@ import 'package:webview_flutter/webview_flutter.dart';
 Future<void> main() async {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 
-  const bool _skipDueToIssue86757 = true;
-
   final HttpServer server = await HttpServer.bind(InternetAddress.anyIPv4, 0);
   server.forEach((HttpRequest request) {
     if (request.uri.path == '/hello.txt') {
@@ -45,10 +43,10 @@ Future<void> main() async {
   final String secondaryUrl = '$prefixUrl/secondary.txt';
   final String headersUrl = '$prefixUrl/headers';
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('initialUrl', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
         Completer<WebViewController>();
+    final Completer<void> pageFinishedCompleter = Completer<void>();
     await tester.pumpWidget(
       Directionality(
         textDirection: TextDirection.ltr,
@@ -58,18 +56,22 @@ Future<void> main() async {
           onWebViewCreated: (WebViewController controller) {
             controllerCompleter.complete(controller);
           },
+          onPageFinished: pageFinishedCompleter.complete,
         ),
       ),
     );
+
     final WebViewController controller = await controllerCompleter.future;
+    await pageFinishedCompleter.future;
+
     final String? currentUrl = await controller.currentUrl();
     expect(currentUrl, primaryUrl);
-  }, skip: _skipDueToIssue86757);
+  });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('loadUrl', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
         Completer<WebViewController>();
+    final StreamController<String> pageLoads = StreamController<String>();
     await tester.pumpWidget(
       Directionality(
         textDirection: TextDirection.ltr,
@@ -79,14 +81,20 @@ Future<void> main() async {
           onWebViewCreated: (WebViewController controller) {
             controllerCompleter.complete(controller);
           },
+          onPageFinished: (String url) {
+            pageLoads.add(url);
+          },
         ),
       ),
     );
     final WebViewController controller = await controllerCompleter.future;
+
     await controller.loadUrl(secondaryUrl);
-    final String? currentUrl = await controller.currentUrl();
-    expect(currentUrl, secondaryUrl);
-  }, skip: _skipDueToIssue86757);
+    await expectLater(
+      pageLoads.stream.firstWhere((String url) => url == secondaryUrl),
+      completion(secondaryUrl),
+    );
+  });
 
   testWidgets('evaluateJavascript', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
@@ -110,7 +118,6 @@ Future<void> main() async {
     expect(result, equals('2'));
   });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('loadUrl with headers', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
         Completer<WebViewController>();
@@ -149,15 +156,14 @@ Future<void> main() async {
     final String content = await controller
         .runJavascriptReturningResult('document.documentElement.innerText');
     expect(content.contains('flutter_test_header'), isTrue);
-  }, skip: Platform.isAndroid && _skipDueToIssue86757);
+  });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('JavascriptChannel', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
         Completer<WebViewController>();
     final Completer<void> pageStarted = Completer<void>();
     final Completer<void> pageLoaded = Completer<void>();
-    final List<String> messagesReceived = <String>[];
+    final Completer<String> channelCompleter = Completer<String>();
     await tester.pumpWidget(
       Directionality(
         textDirection: TextDirection.ltr,
@@ -174,7 +180,7 @@ Future<void> main() async {
             JavascriptChannel(
               name: 'Echo',
               onMessageReceived: (JavascriptMessage message) {
-                messagesReceived.add(message.message);
+                channelCompleter.complete(message.message);
               },
             ),
           },
@@ -191,10 +197,11 @@ Future<void> main() async {
     await pageStarted.future;
     await pageLoaded.future;
 
-    expect(messagesReceived, isEmpty);
+    expect(channelCompleter.isCompleted, isFalse);
     await controller.runJavascript('Echo.postMessage("hello");');
-    expect(messagesReceived, equals(<String>['hello']));
-  }, skip: Platform.isAndroid && _skipDueToIssue86757);
+
+    await expectLater(channelCompleter.future, completion('hello'));
+  });
 
   testWidgets('resize webview', (WidgetTester tester) async {
     final Completer<void> initialResizeCompleter = Completer<void>();
@@ -263,7 +270,6 @@ Future<void> main() async {
     expect(customUserAgent2, 'Custom_User_Agent2');
   });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('use default platform userAgent after webView is rebuilt',
       (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
@@ -313,7 +319,7 @@ Future<void> main() async {
 
     final String customUserAgent2 = await _getUserAgent(controller);
     expect(customUserAgent2, defaultPlatformUserAgent);
-  }, skip: Platform.isAndroid && _skipDueToIssue86757);
+  });
 
   group('Video playback policy', () {
     late String videoTestBase64;
@@ -798,7 +804,6 @@ Future<void> main() async {
   });
 
   group('Programmatic Scroll', () {
-    // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
     testWidgets('setAndGetScrollPosition', (WidgetTester tester) async {
       const String scrollTestPage = '''
         <!DOCTYPE html>
@@ -873,7 +878,7 @@ Future<void> main() async {
       scrollPosY = await controller.getScrollY();
       expect(scrollPosX, X_SCROLL * 2);
       expect(scrollPosY, Y_SCROLL * 2);
-    }, skip: Platform.isAndroid && _skipDueToIssue86757);
+    });
   });
 
   // Minimial end-to-end testing of the legacy Android implementation.
@@ -889,7 +894,7 @@ Future<void> main() async {
     testWidgets('initialUrl', (WidgetTester tester) async {
       final Completer<WebViewController> controllerCompleter =
           Completer<WebViewController>();
-      final Completer<void> loadCompleter = Completer<void>();
+      final Completer<void> pageFinishedCompleter = Completer<void>();
       await tester.pumpWidget(
         Directionality(
           textDirection: TextDirection.ltr,
@@ -899,18 +904,18 @@ Future<void> main() async {
             onWebViewCreated: (WebViewController controller) {
               controllerCompleter.complete(controller);
             },
-            onPageFinished: (String url) {
-              loadCompleter.complete();
-            },
+            onPageFinished: pageFinishedCompleter.complete,
           ),
         ),
       );
+
       final WebViewController controller = await controllerCompleter.future;
-      await loadCompleter.future;
+      await pageFinishedCompleter.future;
+
       final String? currentUrl = await controller.currentUrl();
       expect(currentUrl, primaryUrl);
     });
-  }, skip: !Platform.isAndroid || _skipDueToIssue86757);
+  }, skip: !Platform.isAndroid);
 
   group('NavigationDelegate', () {
     const String blankPage = '<!DOCTYPE html><head></head><body></body></html>';
@@ -1149,7 +1154,6 @@ Future<void> main() async {
     expect(currentUrl, primaryUrl);
   });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets('target _blank opens in same window',
       (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =
@@ -1175,9 +1179,8 @@ Future<void> main() async {
     await pageLoaded.future;
     final String? currentUrl = await controller.currentUrl();
     expect(currentUrl, primaryUrl);
-  }, skip: Platform.isAndroid && _skipDueToIssue86757);
+  });
 
-  // TODO(bparrishMines): skipped due to https://github.com/flutter/flutter/issues/86757
   testWidgets(
     'can open new window and go back',
     (WidgetTester tester) async {
@@ -1213,55 +1216,61 @@ Future<void> main() async {
       expect(controller.canGoBack(), completion(true));
       await controller.goBack();
       await pageLoaded.future;
-      expect(controller.currentUrl(), completion(primaryUrl));
+      await expectLater(controller.currentUrl(), completion(primaryUrl));
     },
-    skip: _skipDueToIssue86757,
   );
 
   testWidgets(
     'clearCache should clear local storage',
     (WidgetTester tester) async {
       final Completer<WebViewController> controllerCompleter =
           Completer<WebViewController>();
-      final Completer<void> onPageFinished = Completer<void>();
+
+      Completer<void> pageLoadCompleter = Completer<void>();
+
       await tester.pumpWidget(
         Directionality(
           textDirection: TextDirection.ltr,
           child: WebView(
             key: GlobalKey(),
             initialUrl: primaryUrl,
             javascriptMode: JavascriptMode.unrestricted,
-            onPageFinished: (_) => onPageFinished.complete(),
+            onPageFinished: (_) => pageLoadCompleter.complete(),
             onWebViewCreated: (WebViewController controller) {
               controllerCompleter.complete(controller);
             },
           ),
         ),
       );
 
-      final WebViewController controller = await controllerCompleter.future;
-      await onPageFinished.future;
+      await pageLoadCompleter.future;
+      pageLoadCompleter = Completer<void>();
 
+      final WebViewController controller = await controllerCompleter.future;
       await controller.runJavascript('localStorage.setItem("myCat", "Tom");');
-
-      expect(
-        controller.runJavascriptReturningResult(
-          'localStorage.getItem("myCat");',
-        ),
-        completion(_webviewString('Tom')),
+      final String myCatItem = await controller.runJavascriptReturningResult(
+        'localStorage.getItem("myCat");',
       );
+      expect(myCatItem, _webviewString('Tom'));
 
       await controller.clearCache();
+      await pageLoadCompleter.future;
 
-      expect(
-        controller.runJavascriptReturningResult(
+      late final String? nullItem;
+      try {
+        nullItem = await controller.runJavascriptReturningResult(
           'localStorage.getItem("myCat");',
-        ),
-        completion(_webviewNull()),
-      );
+        );
+      } catch (exception) {
+        if (defaultTargetPlatform == TargetPlatform.iOS &&
+            exception is ArgumentError &&
+            (exception.message as String).contains(
+                'Result of JavaScript execution returned a `null` value.')) {
+          nullItem = '<null>';
+        }
+      }
+      expect(nullItem, _webviewNull());
     },
-    // TODO(bparrishMines): Unskip once https://github.com/flutter/plugins/pull/5086 lands and is published.
-    skip: Platform.isAndroid,
   );
 }