flutter_test_behavior

Interact with Flutter Widgets the same way the user does.

Simple example

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter_test_behavior/flutter_test_behavior.dart';
import 'package:mocktail/mocktail.dart';

class FakeEvents {
  void onPress() {}
  void onChanged(String? text) {}
}

class MockFakeEvents extends Mock implements FakeEvents {}

// ...
testWidgets('Should perform a tap on Button', (tester) async {
  final FakeEvents events = MockFakeEvents();

  // Create an UserEvent to simulate user interactions with Widgets
  final button = UserEvent(tester, Key('button'));

  await tester.pumpWidget(
    MaterialApp(
      home: Scaffold(
        body: Container(
          child: TextButton(
            key: Key('button'),
            onPressed: events.onPress,
            child: Text('Click me'),
          ),
        ),
      ),
    ),
  );

  await button.tap();

  await tester.pump();

  verify(() => events.onPress()).called(1);
});

API

The API is very straightforward. It will bring the same behavior as a user would interact with any screen. Every action called from UserEvent instance is asynchronous.

UserEvent(WidgetTester, Key)

Every instance should have a WidgetTester and Key. It will be responsible to retrieve the correct Widget by Key from Widget tree and make some actions using the WidgetTester. Every Widget where users could interact with should have its own UserEvent instance.

final button = UserEvent(tester, Key('button'));

tap()

Trigger a tap event from WidgetTester using the UserEvent instance and its Widget Key.

final button = UserEvent(tester, Key('button'));

await button.tap();

type(String text)

Trigger an enterText event from WidgetTester using the UserEvent instance and its Widget Key. To simulate a user interaction correctly, every character from text will trigger an enterText event and starts with a tap event if was not focused.

final input = UserEvent(tester, Key('input'));

// tap() will trigger once because input is not focused
// type() will trigger 5 times because hello has 5 characteres
await input.type('hello');

erase()

Trigger an enterText event from WidgetTester using the UserEvent instance and its Widget Key. To simulate a user interaction correctly, every character it is typed before will trigger an enterText event until empty string and starts with a tap event if was not focused.

final input = UserEvent(tester, Key('input'));

// tap() will trigger tap event once because input is not focused
// type() will trigger enterText event for 'h'
// type() will trigger enterText event for 'he'
// type() will trigger enterText event for 'hel'
// type() will trigger enterText event for 'hell'
// type() will trigger enterText event for 'hello'
await input.type('hello');

// tap() won't trigger because input is already focused
// type() will trigger enterText event for 'hell'
// type() will trigger enterText event for 'hel'
// type() will trigger enterText event for 'he'
// type() will trigger enterText event for 'h'
// type() will trigger enterText event for ''
await input.erase();

widget<T extends Widget>()

Get the most recent instance from a Widget using the UserEvent instance and its Widget Key. Useful to assert some widget property.

final input = UserEvent(tester, Key('input'));

// widgetInput could access a TextField interface
// to assert some property
TextField widgetInput = input.widget<TextField>();

Libraries

flutter_test_behavior