To define : how should testeroids behave if : 
- we don't mark when_Clear_is_called as abstract
- we have a test in when_Clear_is_called.

Should it fail ? should the tests run ? 

how should we formalize if we want a test to only happen in the context of when_Clear_is_called, but not on its refined inherited contexts ? 

those are all design questions that need to be addressed, formalized and documented.