slapos_accounting: test: use PinnedDateTime from mixin

master/bt5/slapos_accounting/TestTemplateItem/portal_components/test.erp5.testSlapOSERP5AccountingScenario.py

@@ -6,24 +6,10 @@
 ##############################################################################
 
 from erp5.component.test.testSlapOSERP5VirtualMasterScenario import TestSlapOSVirtualMasterScenarioMixin
+from erp5.component.test.SlapOSTestCaseMixin import PinnedDateTime
 from DateTime import DateTime
 
 
-class PinnedDateTime(object):
-  """
-  Context manager for changing the zope date
-  """
-  def __init__(self, testinstance, datetime):
-    self.datetime = datetime
-    self.testinstance = testinstance
-
-  def __enter__(self):
-    self.testinstance.pinDateTime(self.datetime)
-
-  def __exit__(self, *args, **kw):
-    self.testinstance.unpinDateTime()
-
-
 class TestSlapOSAccountingScenario(TestSlapOSVirtualMasterScenarioMixin):
 
   def bootstrapAccountingTest(self):