[Zope] ZopeTestCase and INSTANCE_HOME

Zope 2.7, ZTC 0.8.6 When framework.py imports the Testing package, INSTANCE_HOME is overwritten. More precisely it happens in lib/python/Testing/__init__.py: ---------------------------------------------------- cfg = App.config.getConfiguration() # Set the INSTANCE_HOME to the Testing package directory cfg.instancehome = os.path.dirname(__file__) # Make sure this change is propogated to all the legacy locations for # this information. App.config.setConfiguration(cfg) ---------------------------------------------------- os.getenv("INSTANCE_HOME") will be <zope_installation>/lib/python/Testing after this, regardless of its original value. Is there any way to prevent ZTC and/or the Testing package from doing this? Regards, Sandor