refactored deprecated pymongo methods in tests

- remove/count/add_user/insert
- added pymongo_support

tests/document/class_methods.py

@@ -2,6 +2,7 @@
 import unittest
 
 from mongoengine import *
+from mongoengine.pymongo_support import list_collection_names
 
 from mongoengine.queryset import NULLIFY, PULL
 from mongoengine.connection import get_db
@@ -27,9 +28,7 @@ class ClassMethodsTest(unittest.TestCase):
         self.Person = Person
 
     def tearDown(self):
-        for collection in self.db.collection_names():
-            if 'system.' in collection:
-                continue
+        for collection in list_collection_names(self.db):
             self.db.drop_collection(collection)
 
     def test_definition(self):
@@ -66,10 +65,10 @@ class ClassMethodsTest(unittest.TestCase):
         """
         collection_name = 'person'
         self.Person(name='Test').save()
-        self.assertIn(collection_name, self.db.collection_names())
+        self.assertIn(collection_name, list_collection_names(self.db))
 
         self.Person.drop_collection()
-        self.assertNotIn(collection_name, self.db.collection_names())
+        self.assertNotIn(collection_name, list_collection_names(self.db))
 
     def test_register_delete_rule(self):
         """Ensure that register delete rule adds a delete rule to the document
@@ -340,7 +339,7 @@ class ClassMethodsTest(unittest.TestCase):
             meta = {'collection': collection_name}
 
         Person(name="Test User").save()
-        self.assertIn(collection_name, self.db.collection_names())
+        self.assertIn(collection_name, list_collection_names(self.db))
 
         user_obj = self.db[collection_name].find_one()
         self.assertEqual(user_obj['name'], "Test User")
@@ -349,7 +348,7 @@ class ClassMethodsTest(unittest.TestCase):
         self.assertEqual(user_obj.name, "Test User")
 
         Person.drop_collection()
-        self.assertNotIn(collection_name, self.db.collection_names())
+        self.assertNotIn(collection_name, list_collection_names(self.db))
 
     def test_collection_name_and_primary(self):
         """Ensure that a collection with a specified name may be used.