Listens to attempts to look up stubbing answer for given mocks. This class is internal for now.
How does it work?
When method is called on the mock object, Mockito looks for any answer (stubbing) declared on that mock.
If the stubbed answer is found, that answer is invoked (value returned, thrown exception, etc.).
If the answer is not found (e.g. that invocation was not stubbed on the mock), mock's default answer is used.
This listener implementation is notified when Mockito looked up an answer for invocation on a mock.
If we make this interface a part of public API (and we should):
- make the implementation unified with InvocationListener (for example: common parent, marker interface MockObjectListener
single method for adding listeners so long they inherit from the parent)
- make the error handling strict
so that Mockito provides decent message when listener fails due to poor implementation.