flutter-testing_skill

Overview

This skill provides practical, comprehensive guidance for testing Flutter apps across unit, widget, and integration tests. It explains when to use each test type, how to mock plugins and platform channels, and how to run and debug tests in different build modes. The content focuses on actionable patterns, common errors, and CI-friendly workflows.

How this skill works

The skill inspects common testing needs and recommends the appropriate test level: unit tests for isolated logic, widget tests for UI components and interactions, and integration tests for full end-to-end flows. It shows concrete examples for test structure, finding widgets, user interactions, mocking platform channels, and performance measurement. It also covers build modes (debug/profile/release), plugin testing, and running tests across platforms and CI.

When to use it

• Write unit tests for pure functions, business logic, and state management
• Use widget tests to verify rendering, interactions, and layout under different conditions
• Run integration tests for complete user flows and multi-screen navigation
• Mock platform channels when code depends on plugins or native APIs
• Profile performance in profile mode and validate release-mode behavior

Best practices

• Follow the test pyramid: many unit/widget tests, fewer integration tests
• Name tests descriptively and use Arrange-Act-Assert structure
• Keep tests independent; avoid shared state between tests
• Mock external services and platform channels to keep tests fast and reliable
• Run tests in CI and include coverage reporting

Example use cases

• Unit test a data transformer or validation function with Mockito for external calls
• Widget test a form: find fields, enter text, tap submit, assert validation messages
• Integration test login flow across screens on an emulator or device
• Mock a plugin method channel in widget tests to simulate native responses
• Measure scrolling performance with tester.trace and analyze timeline frames