🕊 mockingjay

Developed with 💙 by Very Good Ventures 🦄

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A package that makes it easy to mock, test and verify navigation calls in Flutter. It works in tandem with mocktail, allowing you to mock a navigator the same way you would any other object, making it easier to test navigation behavior independently from the UI it's supposed to render.

Usage

To use the package in your tests, add it to your dev dependencies in your pubspec.yaml:

dev_dependencies:
  mockingjay: ^0.1.0

Then, in your tests, create a MockNavigator class like so:

import 'package:mockingjay/mockingjay.dart';

final navigator = MockNavigator();

Now you can create a new MockNavigator and pass it to a MockNavigatorProvider.

Any widget looking up the nearest Navigator.of(context) from that point will now receive the MockNavigator, allowing you to mock (using when) and verify any navigation calls. Use the included matchers to more easily match specific route names and types.

Note: make sure the MockNavigatorProvider is constructed below the MaterialApp. Otherwise, any Navigator.of(context) call will return a real NavigatorState instead of the mock.

Example

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockingjay/mockingjay.dart';

class MyHomePage extends StatelessWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: TextButton(
        onPressed: () => Navigator.of(context).push(MySettingsPage.route()),
        child: const Text('Navigate'),
      ),
    );
  }
}

class MySettingsPage extends StatelessWidget {
  const MySettingsPage({Key? key}) : super(key: key);

  static Route route() {
    return MaterialPageRoute(
      builder: (_) => const MySettingsPage(),
      settings: const RouteSettings(name: '/settings'),
    );
  }

  @override
  Widget build(BuildContext context) {
    return const Scaffold();
  }
}

void main() {
  testWidgets('pushes SettingsPage when TextButton is tapped', (tester) async {
    final navigator = MockNavigator();
    when(() => navigator.push(any())).thenAnswer((_) async {});

    await tester.pumpWidget(
      MaterialApp(
        home: MockNavigatorProvider(
          navigator: navigator,
          child: const MyHomePage(),
        ),
      ),
    );

    await tester.tap(find.byType(TextButton));

    verify(
      () => navigator.push(any(that: isRoute<void>(named: '/settings'))),
    ).called(1);
  });
}