Add tests for scaffold drawer and end drawer (#149383)

Contributes to flutter/flutter#130459

It adds a test for
- `examples/api/lib/material/scaffold/scaffold.drawer.0.dart`
- `examples/api/lib/material/scaffold/scaffold.end_drawer.0.dart`

Author: ValentinVignal

dev/bots/check_code_samples.dart

@@ -342,8 +342,6 @@ final Set<String> _knownMissingTests = <String>{
   'examples/api/test/material/search_anchor/search_anchor.2_test.dart',
   'examples/api/test/material/about/about_list_tile.0_test.dart',
   'examples/api/test/material/selection_area/selection_area.0_test.dart',
-  'examples/api/test/material/scaffold/scaffold.end_drawer.0_test.dart',
-  'examples/api/test/material/scaffold/scaffold.drawer.0_test.dart',
   'examples/api/test/material/scaffold/scaffold_messenger.of.0_test.dart',
   'examples/api/test/material/scaffold/scaffold_messenger.0_test.dart',
   'examples/api/test/material/scaffold/scaffold_state.show_bottom_sheet.0_test.dart',

examples/api/test/material/scaffold/scaffold.drawer.0_test.dart

@@ -0,0 +1,55 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/scaffold/scaffold.drawer.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('The page should contain a drawer than can be opened and closed', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.DrawerExampleApp(),
+    );
+
+    expect(find.byType(Drawer), findsNothing);
+
+    // Open the drawer by tapping the button at the center of the screen.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Open Drawer'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsOne);
+    expect(tester.getCenter(
+      find.byType(Drawer)).dx,
+      lessThan(400),
+      reason: 'The drawer should be on the left side of the screen',
+    );
+    expect(find.text('This is the Drawer'), findsOne);
+
+    // Close the drawer by tapping the button inside the drawer.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close Drawer'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsNothing);
+
+    // Open the drawer by tapping the drawer button in the app bar.
+    expect(tester.getCenter(
+      find.byType(DrawerButton)).dx,
+      lessThan(400),
+      reason: 'The drawer button should be on the left side of the app bar',
+    );
+    await tester.tap(find.byType(DrawerButton));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsOne);
+    expect(find.text('This is the Drawer'), findsOne);
+
+    // Close the drawer by tapping outside the drawer.
+    final Rect drawerRect = tester.getRect(find.byType(Drawer));
+    final Offset outsideDrawer = drawerRect.centerRight + const Offset(50, 0);
+    await tester.tapAt(outsideDrawer);
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsNothing);
+  });
+}

examples/api/test/material/scaffold/scaffold.end_drawer.0_test.dart

@@ -0,0 +1,55 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/scaffold/scaffold.end_drawer.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('The page should contain an end drawer than can be opened and closed', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.EndDrawerExampleApp(),
+    );
+
+    expect(find.byType(Drawer), findsNothing);
+
+    // Open the drawer by tapping the button at the center of the screen.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Open End Drawer'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsOne);
+    expect(tester.getCenter(
+      find.byType(Drawer)).dx,
+      greaterThan(400),
+      reason: 'The drawer should be on the right side of the screen',
+    );
+    expect(find.text('This is the Drawer'), findsOne);
+
+    // Close the drawer by tapping the button inside the drawer.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close Drawer'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsNothing);
+
+    // Open the drawer by tapping the drawer button in the app bar.
+    expect(tester.getCenter(
+      find.byType(EndDrawerButton)).dx,
+      greaterThan(400),
+      reason: 'The drawer button should be on the right side of the app bar',
+    );
+    await tester.tap(find.byType(EndDrawerButton));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsOne);
+    expect(find.text('This is the Drawer'), findsOne);
+
+    // Close the drawer by tapping outside the drawer.
+    final Rect drawerRect = tester.getRect(find.byType(Drawer));
+    final Offset outsideDrawer = drawerRect.centerLeft - const Offset(50, 0);
+    await tester.tapAt(outsideDrawer);
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Drawer), findsNothing);
+  });
+}