Updates to ComplexFields

Required now means they cannot be empty [#302]

tests/fields.py

@@ -526,7 +526,7 @@ class FieldTest(unittest.TestCase):
 
         self.assertRaises(ValidationError, e.save)
 
-    def test_list_field_required(self):
+    def test_complex_field_required(self):
         """Ensure required cant be None / Empty"""
 
         class Simple(Document):
@@ -538,6 +538,15 @@ class FieldTest(unittest.TestCase):
 
         self.assertRaises(ValidationError, e.save)
 
+        class Simple(Document):
+            mapping = DictField(required=True)
+
+        Simple.drop_collection()
+        e = Simple()
+        e.mapping = {}
+
+        self.assertRaises(ValidationError, e.save)
+
     def test_list_field_complex(self):
         """Ensure that the list fields can handle the complex types."""