Flask: I need to do testing without a database

I’m required to create API endpoints with flask and store any data on a list. I have to test these endpoints using a list. I cannot use a database. I need a way to clear the list in my tearDown every time I do a test. I should be able post an item to the list in every test, and use that item in the test e.g. if I’m testing whether I can edit an item, I should be able to post an item first and then edit it.

Is there a way to do this?