Reland "Implements the navigator page api (#50362)" (#53708)

This reverts commit aee9e94c21.

packages/flutter/test/widgets/navigator_test.dart

@@ -1708,6 +1708,666 @@ void main() {
     await tester.pump(const Duration(seconds: 1));
     expect(tickCount, 4);
   });
+
+  group('Page api', (){
+    Widget buildNavigator(
+      List<Page<dynamic>> pages,
+      PopPageCallback onPopPage, [
+        GlobalKey<NavigatorState> key,
+        TransitionDelegate<dynamic> transitionDelegate
+      ]) {
+      return MediaQuery(
+        data: MediaQueryData.fromWindow(WidgetsBinding.instance.window),
+        child: Localizations(
+          locale: const Locale('en', 'US'),
+          delegates: const <LocalizationsDelegate<dynamic>>[
+            DefaultMaterialLocalizations.delegate,
+            DefaultWidgetsLocalizations.delegate
+          ],
+          child: Directionality(
+            textDirection: TextDirection.ltr,
+            child: Navigator(
+              key: key,
+              pages: pages,
+              onPopPage: onPopPage,
+              transitionDelegate: transitionDelegate ?? const DefaultTransitionDelegate<dynamic>(),
+            ),
+          ),
+        ),
+      );
+    }
+
+    testWidgets('can initialize with pages list', (WidgetTester tester) async {
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      final List<TestPage> myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name:'initial'),
+        const TestPage(key: ValueKey<String>('2'), name:'second'),
+        const TestPage(key: ValueKey<String>('3'), name:'third'),
+      ];
+
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      expect(find.text('third'), findsOneWidget);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('initial'), findsNothing);
+
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('third'), findsNothing);
+      expect(find.text('second'), findsOneWidget);
+      expect(find.text('initial'), findsNothing);
+
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('third'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('initial'), findsOneWidget);
+    });
+
+    testWidgets('can push and pop pages using page api', (WidgetTester tester) async {
+      Animation<double> secondaryAnimationOfRouteOne;
+      Animation<double> primaryAnimationOfRouteOne;
+      Animation<double> secondaryAnimationOfRouteTwo;
+      Animation<double> primaryAnimationOfRouteTwo;
+      Animation<double> secondaryAnimationOfRouteThree;
+      Animation<double> primaryAnimationOfRouteThree;
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      List<Page<dynamic>> myPages = <Page<dynamic>>[
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('1'),
+          name:'initial',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteOne = secondaryAnimation;
+                primaryAnimationOfRouteOne = animation;
+                return const Text('initial');
+              },
+            );
+          },
+        ),
+      ];
+
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      expect(find.text('initial'), findsOneWidget);
+
+      myPages = <Page<dynamic>>[
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('1'),
+          name:'initial',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteOne = secondaryAnimation;
+                primaryAnimationOfRouteOne = animation;
+                return const Text('initial');
+              },
+            );
+          },
+        ),
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('2'),
+          name:'second',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteTwo = secondaryAnimation;
+                primaryAnimationOfRouteTwo = animation;
+                return const Text('second');
+              },
+            );
+          },
+        ),
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('3'),
+          name:'third',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteThree = secondaryAnimation;
+                primaryAnimationOfRouteThree = animation;
+                return const Text('third');
+              },
+            );
+          },
+        )
+      ];
+
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      // The third page is transitioning, and the secondary animation of first
+      // page should chain with the third page. The animation of second page
+      // won't start until the third page finishes transition.
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.dismissed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.forward);
+
+      await tester.pump(const Duration(milliseconds: 30));
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.dismissed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.value, 0.1);
+      await tester.pumpAndSettle();
+      // After transition finishes, the routes' animations are correctly chained.
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(find.text('third'), findsOneWidget);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('initial'), findsNothing);
+      // Starts pops the pages using page api and verify the animations chain
+      // correctly.
+
+      myPages = <Page<dynamic>>[
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('1'),
+          name:'initial',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteOne = secondaryAnimation;
+                primaryAnimationOfRouteOne = animation;
+                return const Text('initial');
+              },
+            );
+          },
+        ),
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('2'),
+          name:'second',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteTwo = secondaryAnimation;
+                primaryAnimationOfRouteTwo = animation;
+                return const Text('second');
+              },
+            );
+          },
+        ),
+      ];
+
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      await tester.pump(const Duration(milliseconds: 30));
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.value, 0.9);
+      await tester.pumpAndSettle();
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+    });
+
+    testWidgets('can modify routes history and secondary animation still works', (WidgetTester tester) async {
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      Animation<double> secondaryAnimationOfRouteOne;
+      Animation<double> primaryAnimationOfRouteOne;
+      Animation<double> secondaryAnimationOfRouteTwo;
+      Animation<double> primaryAnimationOfRouteTwo;
+      Animation<double> secondaryAnimationOfRouteThree;
+      Animation<double> primaryAnimationOfRouteThree;
+      List<Page<dynamic>> myPages = <CustomBuilderPage<void>>[
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('1'),
+          name:'initial',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteOne = secondaryAnimation;
+                primaryAnimationOfRouteOne = animation;
+                return const Text('initial');
+              },
+            );
+          },
+        ),
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('2'),
+          name:'second',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteTwo = secondaryAnimation;
+                primaryAnimationOfRouteTwo = animation;
+                return const Text('second');
+              },
+            );
+          },
+        ),
+        CustomBuilderPage<void>(
+          key: const ValueKey<String>('3'),
+          name:'third',
+          routeBuilder: (BuildContext context, RouteSettings settings) {
+            return PageRouteBuilder<void>(
+              settings: settings,
+              pageBuilder: (_, Animation<double> animation, Animation<double> secondaryAnimation) {
+                secondaryAnimationOfRouteThree = secondaryAnimation;
+                primaryAnimationOfRouteThree = animation;
+                return const Text('third');
+              },
+            );
+          },
+        ),
+      ];
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      expect(find.text('third'), findsOneWidget);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('initial'), findsNothing);
+      expect(secondaryAnimationOfRouteOne.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteThree.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteThree.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+
+      myPages = myPages.reversed.toList();
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      // Reversed routes are still chained up correctly.
+      expect(secondaryAnimationOfRouteThree.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteOne.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.completed);
+
+      navigator.currentState.pop();
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 30));
+      expect(secondaryAnimationOfRouteThree.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteOne.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteOne.value, 0.9);
+      await tester.pumpAndSettle();
+      expect(secondaryAnimationOfRouteThree.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteOne.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+
+      navigator.currentState.pop();
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 30));
+      expect(secondaryAnimationOfRouteThree.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteOne.value);
+      expect(primaryAnimationOfRouteTwo.value, 0.9);
+      expect(secondaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      await tester.pumpAndSettle();
+      expect(secondaryAnimationOfRouteThree.value, primaryAnimationOfRouteTwo.value);
+      expect(primaryAnimationOfRouteThree.status, AnimationStatus.completed);
+      expect(secondaryAnimationOfRouteTwo.value, primaryAnimationOfRouteOne.value);
+      expect(primaryAnimationOfRouteTwo.status, AnimationStatus.dismissed);
+      expect(secondaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+      expect(primaryAnimationOfRouteOne.status, AnimationStatus.dismissed);
+    });
+
+    testWidgets('can work with pageless route', (WidgetTester tester) async {
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      List<TestPage> myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name:'initial'),
+        const TestPage(key: ValueKey<String>('2'), name:'second'),
+      ];
+
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      expect(find.text('second'), findsOneWidget);
+      expect(find.text('initial'), findsNothing);
+      // Pushes two pageless routes to second page route
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless1'),
+          settings: null,
+        )
+      );
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless2'),
+          settings: null,
+        )
+      );
+      await tester.pumpAndSettle();
+      // Now the history should look like
+      // [initial, second, second-pageless1, second-pageless2].
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsOneWidget);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name:'initial'),
+        const TestPage(key: ValueKey<String>('2'), name:'second'),
+        const TestPage(key: ValueKey<String>('3'), name:'third'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(find.text('third'), findsOneWidget);
+
+      // Pushes one pageless routes to third page route
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('third-pageless1'),
+          settings: null,
+        )
+      );
+      await tester.pumpAndSettle();
+      // Now the history should look like
+      // [initial, second, second-pageless1, second-pageless2, third, third-pageless1].
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsOneWidget);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name:'initial'),
+        const TestPage(key: ValueKey<String>('3'), name:'third'),
+        const TestPage(key: ValueKey<String>('2'), name:'second'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      // Swaps the order without any adding or removing should not trigger any
+      // transition. The routes should update without a pumpAndSettle
+      // Now the history should look like
+      // [initial, third, third-pageless1, second, second-pageless1, second-pageless2].
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsOneWidget);
+      // Pops the route one by one to make sure the order is correct.
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsOneWidget);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(myPages.length, 3);
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsNothing);
+      expect(find.text('second'), findsOneWidget);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(myPages.length, 3);
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsOneWidget);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(myPages.length, 2);
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsNothing);
+      expect(find.text('third'), findsOneWidget);
+      expect(find.text('third-pageless1'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(myPages.length, 2);
+      navigator.currentState.pop();
+      await tester.pumpAndSettle();
+      expect(find.text('initial'), findsOneWidget);
+      expect(find.text('third'), findsNothing);
+      expect(find.text('third-pageless1'), findsNothing);
+      expect(find.text('second'), findsNothing);
+      expect(find.text('second-pageless1'), findsNothing);
+      expect(find.text('second-pageless2'), findsNothing);
+      expect(myPages.length, 1);
+    });
+
+    testWidgets('complex case 1', (WidgetTester tester) async {
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      List<TestPage> myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+      ];
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+
+      // Add initial page route with one pageless route.
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      bool initialPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('initial-pageless1'),
+          settings: null,
+        )
+      ).then((_) => initialPageless1Completed = true);
+      await tester.pumpAndSettle();
+
+      // Pushes second page route with two pageless routes.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      await tester.pumpAndSettle();
+      bool secondPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless1'),
+          settings: null,
+        )
+      ).then((_) => secondPageless1Completed = true);
+      await tester.pumpAndSettle();
+      bool secondPageless2Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless2'),
+          settings: null,
+        )
+      ).then((_) => secondPageless2Completed = true);
+      await tester.pumpAndSettle();
+
+      // Pushes third page route with one pageless route.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      await tester.pumpAndSettle();
+      bool thirdPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('third-pageless1'),
+          settings: null,
+        )
+      ).then((_) => thirdPageless1Completed = true);
+      await tester.pumpAndSettle();
+
+      // Nothing has been popped.
+      expect(initialPageless1Completed, false);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+
+      // Switches order and removes the initial page route.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      // The pageless route of initial page route should be completed.
+      expect(initialPageless1Completed, true);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      await tester.pumpAndSettle();
+      expect(secondPageless1Completed, true);
+      expect(secondPageless2Completed, true);
+      expect(thirdPageless1Completed, false);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('4'), name: 'forth'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator));
+      expect(thirdPageless1Completed, true);
+      await tester.pumpAndSettle();
+      expect(find.text('forth'), findsOneWidget);
+    });
+
+    testWidgets('complex case 1 - with always remove transition delegate', (WidgetTester tester) async {
+      final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+      final AlwaysRemoveTransitionDelegate transitionDelegate = AlwaysRemoveTransitionDelegate();
+      List<TestPage> myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+      ];
+      bool onPopPage(Route<dynamic> route, dynamic result) {
+        myPages.removeWhere((Page<dynamic> page) => route.settings == page);
+        return route.didPop(result);
+      }
+
+      // Add initial page route with one pageless route.
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      bool initialPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('initial-pageless1'),
+          settings: null,
+        )
+      ).then((_) => initialPageless1Completed = true);
+      await tester.pumpAndSettle();
+
+      // Pushes second page route with two pageless routes.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      bool secondPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless1'),
+          settings: null,
+        )
+      ).then((_) => secondPageless1Completed = true);
+      await tester.pumpAndSettle();
+      bool secondPageless2Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('second-pageless2'),
+          settings: null,
+        )
+      ).then((_) => secondPageless2Completed = true);
+      await tester.pumpAndSettle();
+
+      // Pushes third page route with one pageless route.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('1'), name: 'initial'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      bool thirdPageless1Completed = false;
+      navigator.currentState.push(
+        MaterialPageRoute<void>(
+          builder: (BuildContext context) => const Text('third-pageless1'),
+          settings: null,
+        )
+      ).then((_) => thirdPageless1Completed = true);
+      await tester.pumpAndSettle();
+
+      // Nothing has been popped.
+      expect(initialPageless1Completed, false);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+
+      // Switches order and removes the initial page route.
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+        const TestPage(key: ValueKey<String>('2'), name: 'second'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      // The pageless route of initial page route should be removed without complete.
+      expect(initialPageless1Completed, false);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('3'), name: 'third'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      await tester.pumpAndSettle();
+      expect(initialPageless1Completed, false);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+
+      myPages = <TestPage>[
+        const TestPage(key: ValueKey<String>('4'), name: 'forth'),
+      ];
+      await tester.pumpWidget(buildNavigator(myPages, onPopPage, navigator, transitionDelegate));
+      await tester.pump();
+      expect(initialPageless1Completed, false);
+      expect(secondPageless1Completed, false);
+      expect(secondPageless2Completed, false);
+      expect(thirdPageless1Completed, false);
+      expect(find.text('forth'), findsOneWidget);
+    });
+
+  });
 }
 
 class _TickingWidget extends StatefulWidget {
@@ -1742,6 +2402,62 @@ class _TickingWidgetState extends State<_TickingWidget> with SingleTickerProvide
   }
 }
 
+class AlwaysRemoveTransitionDelegate extends TransitionDelegate<void> {
+  @override
+  Iterable<RouteTransitionRecord> resolve({
+    List<RouteTransitionRecord> newPageRouteHistory,
+    Map<RouteTransitionRecord, RouteTransitionRecord> locationToExitingPageRoute,
+    Map<RouteTransitionRecord, List<RouteTransitionRecord>> pageRouteToPagelessRoutes,
+  }) {
+    final List<RouteTransitionRecord> results = <RouteTransitionRecord>[];
+    void handleExitingRoute(RouteTransitionRecord location) {
+      if (!locationToExitingPageRoute.containsKey(location))
+        return;
+
+      final RouteTransitionRecord exitingPageRoute = locationToExitingPageRoute[location];
+      final bool hasPagelessRoute = pageRouteToPagelessRoutes.containsKey(exitingPageRoute);
+
+      exitingPageRoute.markForRemove();
+      results.add(exitingPageRoute);
+
+      if (hasPagelessRoute) {
+        final List<RouteTransitionRecord> pagelessRoutes = pageRouteToPagelessRoutes[exitingPageRoute];
+        for (final RouteTransitionRecord pagelessRoute in pagelessRoutes) {
+          pagelessRoute.markForRemove();
+        }
+      }
+      handleExitingRoute(exitingPageRoute);
+    }
+    handleExitingRoute(null);
+
+    for (final RouteTransitionRecord pageRoute in newPageRouteHistory) {
+      if (pageRoute.isEntering) {
+        pageRoute.markForAdd();
+      }
+      results.add(pageRoute);
+      handleExitingRoute(pageRoute);
+
+    }
+    return results;
+  }
+}
+
+class TestPage extends Page<void> {
+  const TestPage({
+    LocalKey key,
+    String name,
+    Object arguments,
+  }) : super(key: key, name: name, arguments: arguments);
+
+  @override
+  Route<void> createRoute(BuildContext context) {
+    return MaterialPageRoute<void>(
+      builder: (BuildContext context) => Text(name),
+      settings: this,
+    );
+  }
+}
+
 class NoAnimationPageRoute extends PageRouteBuilder<void> {
   NoAnimationPageRoute({WidgetBuilder pageBuilder})
       : super(pageBuilder: (BuildContext context, __, ___) {