Add tests for Android back button

Author: LukasMirbt

packages/go_router/test/shell_route_ios_back_gesture_test.dart renamed to packages/go_router/test/shell_route_system_back_test.dart

@@ -7,13 +7,11 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:go_router/go_router.dart';
 
+import 'test_helpers.dart';
+
 // Regression test for https://github.com/flutter/flutter/issues/120353
 void main() {
   group('iOS back gesture inside a ShellRoute', () {
-    Future<void> backGesture(WidgetTester tester) async {
-      await tester.dragFrom(const Offset(0, 300), const Offset(500, 300));
-    }
-
     testWidgets('pops the top sub-route '
         'when there is an active sub-route', (WidgetTester tester) async {
       debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
@@ -29,7 +27,7 @@ void main() {
       await tester.pumpAndSettle();
       expect(find.text('Comment'), findsOneWidget);
 
-      await backGesture(tester);
+      await simulateIosBackGesture(tester);
       await tester.pumpAndSettle();
       expect(find.text('Post'), findsOneWidget);
 
@@ -47,13 +45,47 @@ void main() {
       await tester.pumpAndSettle();
       expect(find.text('Post'), findsOneWidget);
 
-      await backGesture(tester);
+      await simulateIosBackGesture(tester);
       await tester.pumpAndSettle();
       expect(find.text('Home'), findsOneWidget);
 
       debugDefaultTargetPlatformOverride = null;
     });
   });
+
+  group('Android back button inside a ShellRoute', () {
+    testWidgets('pops the top sub-route '
+        'when there is an active sub-route', (WidgetTester tester) async {
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Comment'), findsOneWidget);
+
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+    });
+
+    testWidgets('pops ShellRoute '
+        'when there are no active sub-routes', (WidgetTester tester) async {
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Home'), findsOneWidget);
+    });
+  });
 }
 
 class _TestApp extends StatefulWidget {

packages/go_router/test/stateful_shell_route_ios_back_gesture_test.dart renamed to packages/go_router/test/stateful_shell_route_system_back_test.dart

@@ -7,13 +7,53 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:go_router/go_router.dart';
 
+import 'test_helpers.dart';
+
 // Regression test for https://github.com/flutter/flutter/issues/120353
 void main() {
   group('iOS back gesture inside a StatefulShellRoute', () {
-    Future<void> backGesture(WidgetTester tester) async {
-      await tester.dragFrom(const Offset(0, 300), const Offset(500, 300));
-    }
+    testWidgets('pops the top sub-route '
+        'when there is an active sub-route', (WidgetTester tester) async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
+
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Comment'), findsOneWidget);
+
+      await simulateIosBackGesture(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('pops StatefulShellRoute '
+        'when there are no active sub-routes', (WidgetTester tester) async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
+
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await simulateIosBackGesture(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Home'), findsOneWidget);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+  });
 
+  group('Android back button inside a StatefulShellRoute', () {
     testWidgets('pops the top sub-route '
         'when there is an active sub-route', (WidgetTester tester) async {
       debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
@@ -29,7 +69,7 @@ void main() {
       await tester.pumpAndSettle();
       expect(find.text('Comment'), findsOneWidget);
 
-      await backGesture(tester);
+      await simulateAndroidBackButton(tester);
       await tester.pumpAndSettle();
       expect(find.text('Post'), findsOneWidget);
 
@@ -47,7 +87,7 @@ void main() {
       await tester.pumpAndSettle();
       expect(find.text('Post'), findsOneWidget);
 
-      await backGesture(tester);
+      await simulateAndroidBackButton(tester);
       await tester.pumpAndSettle();
       expect(find.text('Home'), findsOneWidget);
 

packages/go_router/test/test_helpers.dart

@@ -362,6 +362,10 @@ Future<void> simulateAndroidBackButton(WidgetTester tester) async {
   );
 }
 
+Future<void> simulateIosBackGesture(WidgetTester tester) async {
+  await tester.dragFrom(const Offset(0, 300), const Offset(500, 300));
+}
+
 GoRouterPageBuilder createPageBuilder({
   String? restorationId,
   required Widget child,