flutter-add-widget-test

Use testWidgets with a WidgetTester callback, call pumpWidget to build the widget, locate elements with finders like find.text or find.byType, then assert with expect and matchers such as findsOneWidget. Wrap widgets in MaterialApp when they need theme or directionality.

Use tester.tap(finder) to simulate taps and tester.enterText(finder, 'value') for text fields. After the interaction, call tester.pump() to rebuild the tree, then verify the updated state with expect assertions.

pump triggers a single frame rebuild, suitable for simple state changes like button taps. pumpAndSettle repeatedly pumps frames until no more are scheduled, which is required for animations, transitions, and asynchronous UI updates.

Use tester.scrollUntilVisible with the item finder, a scroll delta, and the scrollable finder to bring off-screen items into view before interacting with them. This ensures the target widget is rendered before tapping or asserting.

Common causes include missing MaterialApp or Directionality wrappers, widgets not yet built because pump was not called after an interaction, or items off-screen in scrollable lists. Verify the finder matches the widget tree and pump appropriately.