Inlay Testing

Testing inlay screens

Screens in an inlay module depend on two singletons that talk to the native host over platform channels: InlayNavigator and KeyValueStorage. In plain widget tests there is no host, so those calls throw MissingPluginException. package:inlay/testing.dart ships in-memory fakes, and both singletons expose a @visibleForTesting instance setter.

Canonical docs: https://github.com/leancodepl/inlay/blob/main/docs/testing.md Reference tests (use both fakes): https://github.com/leancodepl/inlay/tree/main/example/example_module/test

1. Install the fakes in setUp

import 'package:inlay/inlay.dart';
import 'package:inlay/testing.dart';

setUp(() {
  KeyValueStorage.instance = FakeKeyValueStorage();
  InlayNavigator.instance = FakeInlayNavigator();
});

Keep local references when the test needs to assert on them:

late FakeInlayNavigator navigator;
late FakeKeyValueStorage storage;

setUp(() {
  navigator = FakeInlayNavigator();
  storage = FakeKeyValueStorage();
  InlayNavigator.instance = navigator;
  KeyValueStorage.instance = storage;
});

2. Assert navigation with FakeInlayNavigator

It records instead of navigating:

• pushedRoutes — typed routes passed to push(), in call order. Assert with expect(navigator.pushedRoutes, [isA<ContactDetailsPage>()]) and check fields on the typed route.
• pushedPages — raw PageSettings from all dispatch methods, including those produced by push().
• popCount — container pops; maybePop still pops an in-Flutter route when it can.
• nativePopGestureEnabled — last value passed to setNativePopGestureEnabled.

3. Seed and assert state with FakeKeyValueStorage

An in-memory map with the real storage's semantics:

• Seed through the generated store wrapper, not by writing raw keys — the wrapper uses the production key encoding:

  await SoundsNotificationsStore(storage, contactId: 'abc').setMute(true);
  

  The raw backing map storage.data is available for inspection.
• Writes do not fire stream (matching the platform's self-notification suppression), so seeding in setUp won't trigger listeners.
• simulateExternalChange(entries) applies entries and fires stream — this is what a write from another engine or native code looks like to the widget under test. Use it to cover the full store → InlayCubit → widget rebuild chain, then await tester.pump().

4. Shape of a full test

Per screen: pump the widget with its store/cubit built from the fakes, assert the initial render (remember InlayCubit starts in InlayStateLoading — pump until ready), interact and assert writes landed in storage.data / navigation landed in navigator.pushedRoutes, and use simulateExternalChange to assert the screen reacts to changes from elsewhere. The reference tests greeting_screen_test.dart and profile_screen_test.dart in the example module demonstrate all of these patterns — mirror them.

Gotchas

• Reset singletons per test (setUp runs per test — fresh fakes each time prevent state leaking between tests).
• Store getters/setters are async; await them in tests or you'll assert before the write.
• These fakes cover widget tests only. Real cross-boundary behavior (plugin registration, typed results delivered to native, appearance propagation) is host-side territory — the example repo has XCUITest and UiAutomator suites to mirror if you need that: https://github.com/leancodepl/inlay/blob/main/docs/testing.md#reference-tests