remonh87/mocktail

A mock library for Dart inspired by mockito

🍹 mocktail

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Mock library for Dart inspired by mockito.

Mocktail focuses on providing a familiar, simple API for creating mocks in Dart (with null-safety) without the need for manual mocks or code generation.

Creating a Mock

import 'package:mocktail/mocktail.dart';

// A Real Cat class
class Cat {
  String sound() => 'meow!';
  bool likes(String food, {bool isHungry = false}) => false;
  int lives = 9;
}

// A Mock Cat class
class MockCat extends Mock implements Cat {}

void main() {
  // Create a Mock Cat instance
  final cat = MockCat();
}

Stub and Verify Behavior

The MockCat instance can then be used to stub and verify calls.

// Stub the `sound` method.
when(cat).calls('sound').thenReturn('meow');

// Interact with the mock cat instance.
cat.sound();

// Verify the interaction occurred (with matcher support).
verify(cat).calls('sound').times(equals(1));

Additional Usage

// Stub a method before interacting with the mock.
when(cat).calls('sound').thenReturn('purrr!');
expect(cat.sound(), 'purrr!');

// You can interact with the mock multiple times.
expect(cat.sound(), 'purrr!');

// You can change the stub.
when(cat).calls('sound').thenReturn('meow');
expect(cat.sound(), 'meow');

// You can stub getters.
when(cat).calls('lives').thenReturn(10);
expect(cat.lives, 10);

// You can stub a method for specific arguments.
when(cat).calls('likes').withArgs(
  positional: ['fish'],
  named: {'isHungry': false},
).thenReturn(true);
expect(cat.likes('fish'), isTrue);

// You can verify the interaction for specific arguments.
verify(cat).calls('likes').withArgs(
  positional: ['fish'],
  named: {'isHungry': false},
).times(1);

// You can stub a method to throw.
when(cat).calls('sound').thenThrow(Exception('oops'));
expect(() => cat.sound(), throwsA(isA<Exception>()));

// You can calculate stubs dynamically.
final sounds = ['purrr', 'meow'];
when(cat).calls('sound').thenAnswer((_) => sounds.removeAt(0));
expect(cat.sound(), 'purrr');
expect(cat.sound(), 'meow');

Resetting Mocks

reset(cat); // Reset stubs and interactions