Test examples are created right with all callbacks etc.

[newstler]

There was a reason why we used .create method in FactoryBot.example instead of .build. Current tests don't catch if anything's changed when we switch to .build. We need to write tests that prove or refute that .create has being used for purpose.

.build is proposed in:
#524
bullet-train-co/bullet_train#965

[newstler]

Late update: it appeared that current tests detect those quite well so the issue can be closed.