If you preload your test database with all fixture data via the rake task:
And set self.pre_loaded_fixtures to true:
self.pre_loaded_fixtures = true
self.use_transactional_tests = true # the default
Would you expect the fixtures to be deleted and reinserted on every test run (caused by ActiveRecord::FixtureSet.create_fixtures – the same code exercised by the rake task)? Given the documentation on Transactional Tests, I'd imagine this to be unexpected behaviour but, regardless of options configured, fixture data is always reinstalled by the fixtures :all call.