The previous FlutterCompositor unit tests were heavily OCMock-based and in fact only really tested two things:

• that the mock objects we created for the tests do the things we configured them to do.
• that FlutterCompositor's implementation make certain specific calls to objects that aren't part of its public API.

The first of these isn't useful as a test. The second is testing that the implementation is the implementation rather than testing that the compositor has certain behaviour.

FlutterCompositor should be refactored for testability and new tests written that actually exercise the compositor.