testBloc<R extends Bloc<S>, S> function Null safety

  1. @isTest
void testBloc<R extends Bloc<S>, S>(
  1. dynamic description,
  2. {FutureVoidCallback? setup,
  3. required BlocTestBloc<R> bloc,
  4. BlocCallback<R>? expectBefore,
  5. BlocCallback<R>? expectAfter,
  6. required StreamMatcher expectedStates,
  7. required BlocCallback<R> job,
  8. BlocTestTransform<S, dynamic>? transform,
  9. Duration timeout = const Duration(minutes: 1)}

Utility function which abstracts over a dart test to ease off bloc testing

R = Type of bloc S = Type of State


void testBloc<R extends Bloc<S>, S>(
  /// description of the test
  description, {

  /// Any setup before the test e.g. mocking repositories
  FutureVoidCallback? setup,

  /// The bloc which is to be tested in this test must be created in this function
  required BlocTestBloc<R> bloc,

  /// Any assertions that must be checked before any operations are run on the bloc
  BlocCallback<R>? expectBefore,

  /// Any assertions that must be checked just before the bloc is to be dispose (end of test)
  BlocCallback<R>? expectAfter,

  /// States which are considered valid broadcasts by bloc
  required StreamMatcher expectedStates,

  /// All the operations on the bloc must be done in this function
  required BlocCallback<R> job,

  /// Any conversions which will be performed on the state before it is matched against [expectedStates]
  BlocTestTransform<S, dynamic>? transform,
  Duration timeout = const Duration(minutes: 1),
}) {
    (tester) async {
      await tester.runAsync(() async {
        if (setup != null) {
          await setup();
        final _bloc = await bloc();
        final stream = _bloc.stream.where((event) => event != null);

            transform == null
                ? stream
                : stream.map((event) => transform(event!)),

        if (expectBefore != null) {
          await expectBefore(_bloc);

        await job(_bloc);
        // ignore: invalid_use_of_visible_for_testing_member
        await _bloc.dispose();

        if (expectAfter != null) {
          await expectAfter(_bloc);
    timeout: Timeout(timeout),