raise an error when trying to save an abstract document (#1449)

mongoengine/document.py

@@ -313,6 +313,9 @@ class Document(BaseDocument):
         .. versionchanged:: 0.10.7
             Add signal_kwargs argument
         """
+        if self._meta.get('abstract'):
+            raise InvalidDocumentError('Cannot save an abstract document.')
+
         signal_kwargs = signal_kwargs or {}
         signals.pre_save.send(self.__class__, document=self, **signal_kwargs)
 
@@ -828,7 +831,6 @@ class Document(BaseDocument):
         """ Lists all of the indexes that should be created for given
         collection. It includes all the indexes from super- and sub-classes.
         """
-
         if cls._meta.get('abstract'):
             return []
 

tests/document/instance.py

@@ -435,6 +435,15 @@ class InstanceTest(unittest.TestCase):
 
         person.to_dbref()
 
+    def test_save_abstract_document(self):
+        """Saving an abstract document should fail."""
+        class Doc(Document):
+            name = StringField()
+            meta = {'abstract': True}
+
+        with self.assertRaises(InvalidDocumentError):
+            Doc(name='aaa').save()
+
     def test_reload(self):
         """Ensure that attributes may be reloaded.
         """