Allows pushing page based route as pageless route (#114362)

* Allows pushing page based route as pageless route

* update

packages/flutter/test/widgets/navigator_test.dart

@@ -180,6 +180,26 @@ void main() {
     expect('$exception', startsWith('Navigator operation requested with a context'));
   });
 
+  testWidgets('Navigator can push Route created through page class as Pageless route', (WidgetTester tester) async {
+    final GlobalKey<NavigatorState> nav = GlobalKey<NavigatorState>();
+    await tester.pumpWidget(
+      MaterialApp(
+        navigatorKey: nav,
+        home: const Scaffold(
+          body: Text('home'),
+        )
+      )
+    );
+    const MaterialPage<void> page = MaterialPage<void>(child: Text('page'));
+    nav.currentState!.push<void>(page.createRoute(nav.currentContext!));
+    await tester.pumpAndSettle();
+    expect(find.text('page'), findsOneWidget);
+
+    nav.currentState!.pop();
+    await tester.pumpAndSettle();
+    expect(find.text('home'), findsOneWidget);
+  });
+
   testWidgets('Zero transition page-based route correctly notifies observers when it is popped', (WidgetTester tester) async {
     final List<Page<void>> pages = <Page<void>>[
       const ZeroTransitionPage(name: 'Page 1'),
@@ -2758,62 +2778,6 @@ void main() {
       );
     });
 
-    Widget buildFrame(String action) {
-      const TestPage myPage = TestPage(key: ValueKey<String>('1'), name:'initial');
-      final Map<String, WidgetBuilder> routes = <String, WidgetBuilder>{
-        '/' : (BuildContext context) => OnTapPage(
-          id: action,
-          onTap: () {
-            if (action == 'push') {
-              Navigator.of(context).push(myPage.createRoute(context));
-            } else if (action == 'pushReplacement') {
-              Navigator.of(context).pushReplacement(myPage.createRoute(context));
-            } else if (action == 'pushAndRemoveUntil') {
-              Navigator.of(context).pushAndRemoveUntil(myPage.createRoute(context), (_) => true);
-            }
-          },
-        ),
-      };
-
-      return MaterialApp(routes: routes);
-    }
-
-    void checkException(WidgetTester tester) {
-      final dynamic exception = tester.takeException();
-      expect(exception, isFlutterError);
-      final FlutterError error = exception as FlutterError;
-      expect(
-        error.toStringDeep(),
-        equalsIgnoringHashCodes(
-          'FlutterError\n'
-          '   A page-based route should not be added using the imperative api.\n'
-          '   Provide a new list with the corresponding Page to Navigator.pages\n'
-          '   instead.\n',
-        ),
-      );
-    }
-
-    testWidgets('throw if add page-based route using the imperative api - push', (WidgetTester tester) async {
-      await tester.pumpWidget(buildFrame('push'));
-      await tester.tap(find.text('push'));
-      await tester.pumpAndSettle();
-      checkException(tester);
-    });
-
-    testWidgets('throw if add page-based route using the imperative api - pushReplacement', (WidgetTester tester) async {
-      await tester.pumpWidget(buildFrame('pushReplacement'));
-      await tester.tap(find.text('pushReplacement'));
-      await tester.pumpAndSettle();
-      checkException(tester);
-    });
-
-    testWidgets('throw if add page-based route using the imperative api - pushAndRemoveUntil', (WidgetTester tester) async {
-      await tester.pumpWidget(buildFrame('pushAndRemoveUntil'));
-      await tester.tap(find.text('pushAndRemoveUntil'));
-      await tester.pumpAndSettle();
-      checkException(tester);
-    });
-
     testWidgets('throw if page list is empty', (WidgetTester tester) async {
       final List<TestPage> myPages = <TestPage>[];
       final FlutterExceptionHandler? originalOnError = FlutterError.onError;