Testing Flutter Applications

Contents

• Core Testing Strategies
• Architectural Testing Guidelines
• Plugin Testing Guidelines
• Workflows
• Examples

Core Testing Strategies

Balance your testing suite across three main categories to optimize for confidence, maintenance cost, dependencies, and execution speed.

Unit Tests

Use unit tests to verify the correctness of a single function, method, or class under various conditions.

• Mock all external dependencies.
• Do not involve disk I/O, screen rendering, or user actions from outside the test process.
• Execute using the test or flutter_test package.

Widget Tests

Use widget tests (component tests) to ensure a single widget's UI looks and interacts as expected.

• Provide the appropriate widget lifecycle context using WidgetTester.
• Use Finder classes to locate widgets and Matcher constants to verify their existence and state.
• Test views and UI interactions without spinning up the full application.