Determine a strategy to test sha256 with Gitlab rails specs

Gitaly is working on supporting Sha256 repositories. We are not far from fully supporting sha256 in Gitaly. gitlab-org/gitlab however, will need to be fixed to support sha256. The main difference to gitlab-org/gitlab is that sha256 have a 64 character ID eg:

06679d0264be7449384df70423973f0079044480ed8ff8a7b67530976fe3e931

vs. a 40 character sha

85ad34234d39ecbf4127bbade08a3c16c4bba542

This is the only discernible difference in repository data coming back from Gitaly. The first step to supporting sha256 repositories in the rails project is to determine a testing strategy to make sure that any test that deals with object ids works with sha256. It might be as simple as identifying all such tests and adding a test with a sha256 repository.