If a Live Test is interrupted, MailHost may have not been restored yet.

product/ERP5Type/tests/ERP5TypeTestCase.py

@@ -286,9 +286,9 @@ class ERP5TypeTestCaseMixin(ProcessingNodeTestCase, PortalTestCase):
       """Restore original Mail Host
       """
       cls = self.portal.MailHost.__class__
-      assert cls.__bases__[0] is DummyMailHostMixin
-      cls.__bases__ = cls.__bases__[1:]
-      pmc_init_of(cls)
+      if cls.__bases__[0] is DummyMailHostMixin:
+        cls.__bases__ = cls.__bases__[1:]
+        pmc_init_of(cls)
 
     def pinDateTime(self, date_time):
       # pretend time has stopped at a certain date (i.e. the test runs