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command. this app allows a user to tap on a button
to increase a counter.
<code_start>
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
widget build(BuildContext context) {
return const MaterialApp(
title: 'counter app',
home: MyHomePage(title: 'counter app home page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final string title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
widget build(BuildContext context) {
return scaffold(
appBar: AppBar(
title: text(widget.title),
),
body: center(
child: column(
mainAxisAlignment: MainAxisAlignment.center,
children: <widget>[
const text(
'you have pushed the button this many times:',
),
text(
'$_counter',
style: Theme.of(context).textTheme.headlineMedium,
),
],
),
),
floatingActionButton: FloatingActionButton(
// provide a key to this button. this allows finding this
// specific button inside the test suite, and tapping it.
key: const key('increment'),
onPressed: _incrementCounter,
tooltip: 'increment',
child: const Icon(Icons.add),
),
);
}
}
<code_end>
<topic_end>
<topic_start>
2. add the integration_test dependency
next, use the integration_test and flutter_test packages
to write integration tests. add these dependencies to the dev_dependencies
section of the app’s pubspec.yaml file.
<topic_end>
<topic_start>
3. create the test files
create a new directory, integration_test, with an empty app_test.dart file:
<topic_end>
<topic_start>
4. write the integration test
now you can write tests. this involves three steps:
<code_start>
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:integration_test/integration_test.dart';
import 'package:introduction/main.dart';
void main() {
IntegrationTestWidgetsFlutterBinding.ensureInitialized();
group('end-to-end test', () {
testWidgets('tap on the floating action button, verify counter',
(tester) async {
// load app widget.
await tester.pumpWidget(const MyApp());
// verify the counter starts at 0.
expect(find.text('0'), findsOneWidget);
// finds the floating action button to tap on.
final fab = find.byKey(const key('increment'));
// emulate a tap on the floating action button.
await tester.tap(fab);
// trigger a frame.
await tester.pumpAndSettle();
// verify the counter increments by 1.
expect(find.text('1'), findsOneWidget);
});
});
}
<code_end>