testController<C extends BaseController<State>, State> function

@isTest void testController<C extends BaseController<State>, State>(String description, { required C build(), State seed()?, dynamic act(C controller)?, Duration? wait, int skip = 0, dynamic expect()?, dynamic verify(C controller)?, dynamic errors()?, })

Creates a new controller-specific test case with the given description. testController will handle asserting that the controller emits the expected states (in order) after act is executed. testController also handles ensuring that no additional states are emitted by closing the controller stream before evaluating the expectation.

build should be used for all controller initialization and preparation and must return the controller under test.

seed is an optional Function that returns a state which will be used to seed the controller before act is called.

act is an optional callback which will be invoked with the controller under test and should be used to interact with the controller.

skip is an optional int which can be used to skip any number of states. skip defaults to 0.

wait is an optional Duration which can be used to wait for async operations within the controller under test such as debounceTime.

expect is an optional Function that returns a Matcher which the controller under test is expected to emit after act is executed.

verify is an optional callback which is invoked after expect and can be used for additional verification/assertions. verify is called with the controller returned by build.

errors is an optional Function that returns a Matcher which the controller under test is expected to throw after act is executed.

testController(
  'CounterController emits [1] when increment is added',
  build: () => CounterController(),
  act: (controller) => controller.add(CounterEvent.increment),
  expect: () => [1],
);

testController can optionally be used with a seeded state.

testController(
  'CounterController emits [10] when seeded with 9',
  build: () => CounterController(),
  seed: () => 9,
  act: (controller) => controller.add(CounterEvent.increment),
  expect: () => [10],
);

testController can also be used to skip any number of emitted states before asserting against the expected states. skip defaults to 0.

testController(
  'CounterController emits [2] when increment is added twice',
  build: () => CounterController(),
  act: (controller) {
    controller
      ..add(CounterEvent.increment)
      ..add(CounterEvent.increment);
  },
  skip: 1,
  expect: () => [2],
);

testController can also be used to wait for async operations by optionally providing a Duration to wait.

testController(
  'CounterController emits [1] when increment is added',
  build: () => CounterController(),
  act: (controller) => controller.add(CounterEvent.increment),
  wait: const Duration(milliseconds: 300),
  expect: () => [1],
);

testController can also be used to verify internal controller functionality.

testController(
  'CounterController emits [1] when increment is added',
  build: () => CounterController(),
  act: (controller) => controller.add(CounterEvent.increment),
  expect: () => [1],
  verify: (_) {
    verify(() => repository.someMethod(any())).called(1);
  }
);

Note: when using testController with state classes which don't override == and hashCode you can provide an Iterable of matchers instead of explicit state instances.

testController(
 'emits [StateB] when EventB is added',
 build: () => MyController(),
 act: (controller) => controller.add(EventB()),
 expect: () => [isA<StateB>()],
);

Implementation

@isTest
void testController<C extends BaseController<State>, State>(
  String description, {
  required C Function() build,
  State Function()? seed,
  Function(C controller)? act,
  Duration? wait,
  int skip = 0,
  dynamic Function()? expect,
  Function(C controller)? verify,
  dynamic Function()? errors,
}) {
  test.test(description, () async {
    await internalControllerTest<C, State>(
      build: build,
      seed: seed,
      act: act,
      wait: wait,
      skip: skip,
      expect: expect,
      verify: verify,
      errors: errors,
    );
  });
}