add a test with an invalid data type

This reverts commit 7d5caf8368.

docs/changelog.rst

@@ -6,11 +6,6 @@ Development
 ===========
 - (Fill this out as you fix issues and develop your features).
 
-Changes in 0.13.0
-=================
-- POTENTIAL BREAKING CHANGE: Added Unicode support to the `EmailField`, see
-  docs/upgrade.rst for details.
-
 Changes in 0.12.0
 =================
 - POTENTIAL BREAKING CHANGE: Fixed limit/skip/hint/batch_size chaining #1476

docs/upgrade.rst

@@ -6,17 +6,6 @@ Development
 ***********
 (Fill this out whenever you introduce breaking changes to MongoEngine)
 
-0.13.0
-******
-This release adds Unicode support to the `EmailField` and changes its
-structure significantly. Previously, email addresses containing Unicode
-characters didn't work at all. Starting with v0.13.0, domains with Unicode
-characters are supported out of the box, meaning some emails that previously
-didn't pass validation now do. Make sure the rest of your application can
-accept such email addresses. Additionally, if you subclassed the `EmailField`
-in your application and overrode `EmailField.EMAIL_REGEX`, you will have to
-adjust your code to override `EmailField.USER_REGEX`, `EmailField.DOMAIN_REGEX`,
-and potentially `EmailField.UTF8_USER_REGEX`.
 
 0.12.0
 ******

mongoengine/__init__.py

@@ -23,7 +23,7 @@ __all__ = (list(document.__all__) + list(fields.__all__) +
            list(signals.__all__) + list(errors.__all__))
 
 
-VERSION = (0, 13, 0)
+VERSION = (0, 12, 0)
 
 
 def get_version():

mongoengine/base/document.py

@@ -1,6 +1,6 @@
 import copy
 import numbers
-from collections.abc import Hashable
+from collections import Hashable
 from functools import partial
 
 from bson import ObjectId, json_util

mongoengine/document.py

@@ -808,7 +808,7 @@ class Document(BaseDocument):
         collection = cls._get_collection()
         # 746: when connection is via mongos, the read preference is not necessarily an indication that
         # this code runs on a secondary
-        if collection.is_mongos is not None and collection.read_preference.mode > 1:
+        if not collection.is_mongos and collection.read_preference > 1:
             return
 
         # determine if an index which we are creating includes

mongoengine/fields.py

@@ -6,7 +6,7 @@ import socket
 import time
 import uuid
 import warnings
-from collections.abc import Mapping
+from collections import Mapping
 from operator import itemgetter
 
 from bson import Binary, DBRef, ObjectId, SON