You're writing a library, and you know your users pickle your object. Sometimes you add new fields, and this creates a BC problem because old pickles of the objects don't have the needed fields. You'd like to add some tests for this case.
The obvious way to do this is to save some actual pickles from your old version, shove them in your test suite somehow, and make sure you can keep unpickling them. But having hard-coded binary test data is pretty uncool. Is there a way to write tests without having to do some manual binary? I've tried playing around with "faking" the __module__ and __qualname__ fields on a locally declared class (which is intended to simulate the "old" version) but I get errors like "_pickle.PicklingError: Can't pickle : it's not the same object as torch.nn.modules.conv.Conv2d" Is there a good way to do this?