For the clojure-1.0-compatibility branch, copy the fix from http://www.assembla.com/spaces/clojure/tickets/194-clojure-test-use-fixtures-function-composes-fixture-functions-repeatedly

If you call use-fixtures over and over again, it will simply compose the test deeper and deeper into a nesting of the fixture function.
(use-fixtures :each my-cleanup) (deftest my-messy-test […])

Load that a few times and you end up running the equivalent of:
(my-cleanup (my-cleanup (my-cleanup my-messy-test))).