At the risk of necromancing this thread once more:
you can do
Ecto.Adapters.SQL.Sandbox.start_owner!(Repo, sandbox: false)in your DataCase setup
I sometimes use this to peek into the database state when working on a specific test case.
This is especially helpful when testing insert logic, e.g. for bulk upserts. Obviously, you will need to reset the tables manually when you are done to not interfere with other tests.
