WidgetTestHarnessCallback<T extends WidgetTestHarness> typedef

WidgetTestHarnessCallback<T extends WidgetTestHarness> = Future<void> Function(WidgetTestGiven<T>, WidgetTestWhen<T>, WidgetTestThen<T>)

This function is intended to wrap your Widget tests so that you can access the WidgetTestGiven, WidgetTestWhen, and WidgetTestWhen to compose the test case. You will want to create some of your own test support code that is specific to your code under test. It should look something like this:

Implementation

typedef WidgetTestHarnessCallback<T extends WidgetTestHarness> = Future<void>
    Function(WidgetTestGiven<T>, WidgetTestWhen<T>, WidgetTestThen<T>);