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🧪 Testing

Testing of Flutter goes into three categories:

  • unit tests for single function, class or method,
  • widget tests for a single widget,
  • integration tests for whole app or big part of the app.

Example tests can be found in test/ directory.

BLoC​

Strive to test every BLoC thoroughly as it is the source of data for UI and a recipient of events from the system. If it works, then UI will likely work too as it listens closely for updates, and requested actions will take place.

Example test:

blocTest<CounterBloc, CounterState>(
  'decrease actions',
  build: () => CounterBloc(),
  act: (bloc) => [
    for (int i = 0; i < 4; i++) bloc.add(const CounterEvent.decreased())
  ],
  expect: () => const <CounterState>[
    CounterState(value: -1),
    CounterState(value: -2),
    CounterState(value: -3),
    CounterState(value: -4)
  ],
);

Use blocTest to reduce boilerplate compared to classic tests, where managing instances is required.

Widgets​

When creating reusable widget, DO test if it's params do affect the UI as expected.

Testing complex widgets, like whole pages should be done via integration tests.

Integration tests​

Consider implementing integration tests for crucial workflows, eg. logging in. Avoid implementing integration tests for every workflow as updating an app fortified with a lot of integration tests will be difficult. Assume that reusable widgets are working correctly (as those are tested) and focus integration tests on workflow interactions.

Look at Flutter integration testing docs.

We're keeping integration tests in integration_test directory.

To run integration tests, use make run-integration-test.