Closes Issue 21238: New keyword argument `unsafe` to Mock.

It raises `AttributeError` incase of an attribute startswith assert
or assret.

1 files changed, 6 insertions, 2 deletions

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 42cf23a..48e7dd0 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -379,7 +379,7 @@ class NonCallableMock(Base):
     def __init__(
             self, spec=None, wraps=None, name=None, spec_set=None,
             parent=None, _spec_state=None, _new_name='', _new_parent=None,
-            _spec_as_instance=False, _eat_self=None, **kwargs
+            _spec_as_instance=False, _eat_self=None, unsafe=False, **kwargs
         ):
         if _new_parent is None:
             _new_parent = parent
@@ -409,6 +409,7 @@ class NonCallableMock(Base):
         __dict__['_mock_mock_calls'] = _CallList()
 
         __dict__['method_calls'] = _CallList()
+        __dict__['_mock_unsafe'] = unsafe
 
         if kwargs:
             self.configure_mock(**kwargs)
@@ -565,13 +566,16 @@ class NonCallableMock(Base):
 
 
     def __getattr__(self, name):
-        if name == '_mock_methods':
+        if name in {'_mock_methods', '_mock_unsafe'}:
             raise AttributeError(name)
         elif self._mock_methods is not None:
             if name not in self._mock_methods or name in _all_magics:
                 raise AttributeError("Mock object has no attribute %r" % name)
         elif _is_magic(name):
             raise AttributeError(name)
+        if not self._mock_unsafe:
+            if name.startswith(('assert', 'assret')):
+                raise AttributeError(name)
 
         result = self._mock_children.get(name)
         if result is _deleted: