With regards to copyright law and "distribution", there's no distinction. The tests are still being "distributed", just from a different URL. If youtube-dl was in violation before, they still are now.
This is a confusing result. I would not expect any copyright litigant to sacrifice legal advantage for the sake of an adversary's convenience in maintaining complete version control history.
Could there possibly have been a miscommunication over what "remove the tests" meant? Or an offer of compromise outside of legal necessity? Or a bad-faith fulfillment of a promise to "remove the tests"?