more reliable and readable unittest for force push

[extrawurst]

based off of #534 (and #535):

Currently

@WizardOhio24 it looks like the internals of repo_init were unclear: it creates independent temporary test repositories (including an empty commit).

the current unittests both test essentially the same thing:

create **new** repo (a), add empty commit to (a)
create **new** repo (b), add empty commit to (b)
create bare repo (c)

now we commit some temp file to (a)
now we push from (a) to (c)

now we commit some temp file to (b)
test that we cannot push (b) to (c)

now force push (b) to (c) doing a history rewrite

only difference is that the second unittest test_force_push_rewrites_history does some additional checks that the right commit IDs are in (c) at the end.

Desired

1. test_force_push can be simplified to just test that we can overwrite (c) with (b) - no additional file need to be committed

2. a real life use case would be nice where we actually create a repo (a), clone (a) to (b) and then have two commits that collide and test that force does what it should

[amalik18]

I can try this

[amalik18]

How do I assign it to myself?

[extrawurst]

How do I assign it to myself?

Just open a PR when you are ready and mention this issue in it 👍

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.