Mock tests should be independent

[sosnovsky]

          Thank you for your hint. I thought tests were isolated and tests each other don't affect others. But seems like add/generate key affects other tests

Originally posted by @ioanmo226 in #5823 (comment)

[sosnovsky]

Yes, tests should be isolated and don't affect each other, as they're expected to have separate mock environments.
Let's check why adding key affected other tests and fix it.

[sosnovsky]

Thanks for checking, let's leave it for now, I'll move it to Later milestone