Flutter Widget Testing Guide — Golden Tests, Interactions, and Async

Unit tests verify logic. Widget tests verify UI behavior. Here's a complete guide to writing robust widget tests that catch regressions before they hit production.

Basic Widget Test

testWidgets ( 'CounterWidget increments on tap' , ( tester ) async { await tester . pumpWidget ( const MaterialApp ( home: CounterWidget ()));

expect ( find . text ( '0' ), findsOneWidget );

await tester . tap ( find . byIcon ( Icons . add )); await tester . pump ();

expect ( find . text ( '1' ), findsOneWidget ); });

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Async Data Loading

testWidgets ( 'TaskList loads and displays tasks' , ( tester ) async { final mockRepo = MockTaskRepository (); when (() = > mockRepo . getAll ()) . thenAnswer (( _ ) async = > [ Task ( id: '1' , title: 'Buy milk' , isDone: false ), Task ( id: '2' , title: 'Write tests' , isDone: true ), ]);

await tester . pumpWidget ( ProviderScope ( overrides: [ taskRepoProvider .…