There are many tests for int-like objects (which implement custom __index__ or __int__ methods) in different files. There are less tests for float-like objects (with the __float__ method). There are even tests for complex-like (with the __complex__ method) in different files. To simplify maintaining old tests and adding new tests I propose to add general test classes with custom methods __index__, __int__, __float__ or __complex__ which return the specified value or raise an exception. There is already one similar general class: FakePath.

It could be done using unittest.mock, but Mock objects are much more complex and has too much magic, so they can have different behavior than simpler classes with a single special method.