mocktail

# Mocktail Skill This skill defines how to correctly use the `mocktail` package for mocking in Dart and Flutter tests. --- ## 1. Mock vs. Fake vs. Real Object | Use | When | |---|---| | **Real object** | Prefer over mocks when practical. | | **Fake** (`extends Fake`) | Lightweight custom implementation; override only the methods you need. Prefer over mocks when you don't need interaction verification. | | **Mock** (`extends Mock`) | Only when you need to **verify interactions** (call counts, arguments) or stub dynamic responses. | - Never add `@override` methods or implementations to a class extending `Mock`. - Only use mocks if your test has `verify` assertions; otherwise prefer real or fake objects. --- ## 2. Creating Mocks ```dart class MockMyService extends Mock implements MyService {} class FakeMyEvent extends Fake implements MyEvent {} ``` No code generation required — unlike Mockito, Mocktail uses `noSuchMethod` at runtime. --- ## 3. Registering Fallback Values Register fallback values **before** using custom types with argument matchers. Do this in `setUpAll` or at the top of your test: ```dart setUpAll(() { registerFallbackValue(FakeMyEvent()); }); ``` - Required for non-nullable custom types used with `any()`, `captureAny()`, or `captureThat()`. - Register fallback values for **any** custom type used with argument matchers. --- ## 4. Stubbing ```dart final mock = MockMyService(); // Return a value when(() => mock.fetchData()).thenReturn('result')...