Delete the fixtures on a functionnal test


Since couple a day, I block with the delete of my fixtures in my functionnals test. In my controller, I need test a redirect if there are no value.

But i load my fixtures in start of my test and in a specific test I want delete all. Only in this method, not in other method. In API, I discover the method delete_existing_fixtures, who seem the good practice, but I can't find how use it. I have always the information of method not found.

So I want know if anyone has an information for delete my fixtures in a test.