(I discussed this with @jonahwilliams already, but I'm filing this to make sure we're tracking it.)

flutter run test/widget_test.dart is broken after the recent test_api changes. Attempting it will hit various runtime exceptions such as:

NoSuchMethodError: The method 'test' was called on null.
NoSuchMethodError: The method 'setUp' was called on null.
NoSuchMethodError: The method 'tearDown' was called on null.

We document that people can use flutter run on their widget tests to help debug widget tests, so this should be expected to work.