allow to use sets in field choices (#1482)

tests/utils.py

@@ -0,0 +1,22 @@
+import unittest
+
+from mongoengine import connect
+from mongoengine.connection import get_db
+
+MONGO_TEST_DB = 'mongoenginetest'
+
+
+class MongoDBTestCase(unittest.TestCase):
+    """Base class for tests that need a mongodb connection
+    db is being dropped automatically
+    """
+
+    @classmethod
+    def setUpClass(cls):
+        cls._connection = connect(db=MONGO_TEST_DB)
+        cls._connection.drop_database(MONGO_TEST_DB)
+        cls.db = get_db()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls._connection.drop_database(MONGO_TEST_DB)