Include test files in sdists

[toddrme2178]

These files are missing from sdists but are needed for the unit tests as far as I can determine.

[Byron]

Thanks a lot for your contribution!
Right now I am not on a computer in the traditional sense and can’t verify GitPython source-distributions are still working with the change.
Once that is done, I will happily merge.

[Byron]

I just took a look and noticed that this increases the file size to nearly 6MB on a garbage collected git repository. As most people depending on GitPython (as I presume) just want use it, big download sizes add latency to their workflow on installation. They wouldn't benefit from running the tests at all.

Do you think that there is a way to satisfy your needs of making the tests runnable, while keeping the download size for users who are not interested in this small?

[toddrme2178]

One possibility might be to create a small git project just for the tests and include that in the source tree. That has the advantage and disadvantage of being independent of the main source tree (advantage that it is consistent across any change to the source tree, disadvantage that changes to the source tree can highlight errors you didn't think to check). However, I would understand if you think this is too much work and prefer to keep things the way they are.

…

[Byron]

@toddrme2178 Thanks for your reply. I agree, there are options, but they seem to be quite a lot of effort, too, which I believe nobody wants to invest right now.
Therefore and with some regret as some effort is lost, I think it's best to close this PR.