Unit testing with database in CI 3.x

What do you mean by reinitialize MySQL Database?

Back to an empty database or what?

If it's back to an empty database then all you need to do is delete all the tables.

Sorry for the misunderstanding. I meant that I have a database at a certain state. I am testing my models, and some tests insert and delete info from the database, I want the database to go back to the state it was before running the tests.