Steps to reproduce

We have a complex test with rspec, database cleaner, factorygirl. Some runs are deadlocking. Debugging showed that there is a transaction started but not finished.

A simplified case:
https://gist.github.com/mfazekas/ccf9bee10dc4fe23f39d1da1b914993b

Expected behavior

Pass or error, but not a deadlock

Actual behavior

Deadlock. Test doesn't finish

System configuration

Rails version: 5.0.0.beta3
Ruby version: 2.3.0

cannot repro in 4.2.0