What should be committed or ignored in git for Codeception tests?

I look through the Codeception files and I see .gitkeep in the tests/_data/ directory. That is the directory that should hold a database dump. That dump is the database from which the site will be restored. That same directory also, upon initialization, contains a .gitkeep file which indicates to me that the directory "should be committed, but there isn't anything in it right now". Now, I'm not going to commit my database to my repo, but should that one file be ignored or should the whole directory be ignored? Are there other files are directories that should be ignored? Is there a best-practice to follow when working with .git and automated tests?