Fixed interference between consecutive unit tests

tests/abstract_attract_test.py

@@ -1,8 +1,5 @@
 from pillar.tests import PillarTestServer, AbstractPillarTest
 
-from attract import AttractExtension
-from attract.setup import setup_for_attract
-
 MOCK_SVN_URL = 'svn://biserver/mocked'
 
 
@@ -10,13 +7,20 @@ class AttractTestServer(PillarTestServer):
     def __init__(self, *args, **kwargs):
         PillarTestServer.__init__(self, *args, **kwargs)
 
+        from attract import AttractExtension
         self.load_extension(AttractExtension(), '/attract')
 
 
 class AbstractAttractTest(AbstractPillarTest):
     pillar_server_class = AttractTestServer
 
+    def tearDown(self):
+        self.unload_modules('attract')
+        AbstractPillarTest.tearDown(self)
+
     def ensure_project_exists(self, project_overrides=None):
+        from attract.setup import setup_for_attract
+
         project_overrides = dict(
             picture_header=None,
             picture_square=None,