Codeception's DataFactory module contains an ORM module for pushing entities to a database.
I have run into an issue where if the ORM module's EntityManager instance closes in any due to an error (example: failed insert). When the entity manager closes, it stays closed for any future tests that get run.
[Doctrine\ORM\ORMException] The EntityManager is closed.
While I feel it is important to double check your factory definitions and make sure they are correct. I don't feel that an error in one test should impact the rest of my tests unless they are trying to use the same data.
I would like to to see the DataFactory & Doctrine modules set up to create new instances of an entity manager if the original entity manger happens to close.