Prevent prefix "called_" for attributes of safe mock objects

Lib/test/test_unittest/testmock/testmock.py

@@ -1645,12 +1645,15 @@ def test_mock_unsafe(self):
             m.aseert_foo_call()
         with self.assertRaisesRegex(AttributeError, msg):
             m.assrt_foo_call()
+        with self.assertRaisesRegex(AttributeError, msg):
+            m.called_once_with()
         m = Mock(unsafe=True)
         m.assert_foo_call()
         m.assret_foo_call()
         m.asert_foo_call()
         m.aseert_foo_call()
         m.assrt_foo_call()
+        m.called_once_with()
 
     #Issue21262
     def test_assert_not_called(self):

Lib/unittest/mock.py

@@ -653,7 +653,7 @@ def __getattr__(self, name):
         elif _is_magic(name):
             raise AttributeError(name)
         if not self._mock_unsafe:
-            if name.startswith(('assert', 'assret', 'asert', 'aseert', 'assrt')):
+            if name.startswith(('assert', 'assret', 'asert', 'aseert', 'assrt', 'called_')):
                 raise AttributeError(
                     f"{name!r} is not a valid assertion. Use a spec "
                     f"for the mock if {name!r} is meant to be an attribute.")
@@ -1231,7 +1231,7 @@ class or instance) that acts as the specification for the mock object. If
       `return_value` attribute.
 
     * `unsafe`: By default, accessing any attribute whose name starts with
-      *assert*, *assret*, *asert*, *aseert* or *assrt* will raise an
+      *assert*, *assret*, *asert*, *aseert*, *assrt*, or *called_* will raise an
        AttributeError. Passing `unsafe=True` will allow access to
       these attributes.
 

Misc/NEWS.d/next/Library/2023-01-02-16-59-49.gh-issue-100690.2EgWPS.rst

@@ -0,0 +1,3 @@
+Mock objects which are not unsafe will now raise an AttributeError if an
+attribute with the prefix ``called_`` is accessed, in addition to this already
+happening for the prefixes assert, assret, asert, aseert, assrt.