These tests use create_pumper from Autobahn which returns an object with a stop method which returns a Deferred. These tests uses testtools.TestCase.addCleanup to call the pumper stop method. However, testtools.TestCase.addCleanup doesn't wait on Deferred return values unless run_tests_with is set to an AsynchronousDeferredRunTest instance - which these tests do not do.
These tests use
create_pumperfrom Autobahn which returns an object with astopmethod which returns aDeferred. These tests usestesttools.TestCase.addCleanupto call the pumperstopmethod. However,testtools.TestCase.addCleanupdoesn't wait onDeferredreturn values unlessrun_tests_withis set to anAsynchronousDeferredRunTestinstance - which these tests do not do.