don't test that group category is empty, but that it does not already contain what we want to add

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16064 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/tests/testConstraint.py

@@ -76,9 +76,10 @@ class TestConstraint(PropertySheetTestCase):
       some categories for testing them
     """
     category_list = ['testGroup1', 'testGroup2']
-    if len(self.category_tool.group.contentValues()) == 0 :
+    group = self.category_tool.group
+    if 'testGroup1' not in group.contentIds():
       for category_id in category_list:
-        o = self.category_tool.group.newContent(portal_type='Category',
+        o = group.newContent(portal_type='Category',
                              id=category_id)
 
   def stepDeleteObjectModuleContent(self, sequence=None,