What problem does it solve? Writing unit tests in Dart and Flutter often requires isolating code from its dependencies, and doing this incorrectly leads to brittle tests, confusing stubbing errors, and over-mocked suites that are hard to maintain. ## Core Features & Use Cases - Mock Generation: Create mocks with @GenerateMocks or @GenerateNiceMocks and build_runner, following correct annotation and build.yaml conventions. - Stubbing & Verification: Stub return values, errors, and sequential responses with when/thenReturn, then verify call counts and arguments with verify, verifyNever, and untilCalled. - Argument Matching & Capture: Use any, argThat, captureAny, and captureThat to flexibly match and inspect arguments passed to mocked methods. - Use Case: When testing a repository class that depends on an HTTP client, generate a mock client, stub its responses, and verify the correct endpoints were called with the right headers. ## Quick Start Generate a Mockito mock for my ApiClient class, stub its fetch method to return test data, and verify it was called exactly once.
