Format for oneline can be overridden in user's gitconfig. If that's the
case, last_revision_commit_of_file won't work properly, and because of
that last_revision_of_file won't work at all.
Here's what I was getting when running brew tests:
expected: "6bec2de"
got: "\e[33m6bec2dee633f\e[m"
I have abbrev length set to 12, and oneline formatting is more colorful.
So, instead of relying on overrideable format, it should rather specify
"--format=%h" to get only hash, and speciy --abbrev=7 to force abbrev
length to be 7
After this commit tests are passing for me.
461bb20b7c