Sometimes works and sometimes does not because of the non-deterministic aspect of MockInBean / SpyInbean definition parsing.

• Works when the mock is created before the spy (because the spy will use the fields already injected into the bean).
• Does not work when the spy is created before the mock (because the mock will be injected inside the spring bean and not the spy).

This is because the Spy does not delegate to the original object but creates a copy (as documented in https://javadoc.io/doc/org.mockito/mockito-core/latest/org/mockito/Spy.html).

Could be fixed by also injecting mocks into spies.