Issue #20189: Four additional builtin types (PyTypeObject,

PyMethodDescr_Type, _PyMethodWrapper_Type, and PyWrapperDescr_Type)
have been modified to provide introspection information for builtins.
Also: many additional Lib, test suite, and Argument Clinic fixes.

Lib/unittest/mock.py

@@ -112,11 +112,24 @@ def _check_signature(func, mock, skipfirst, instance=False):
 def _copy_func_details(func, funcopy):
     funcopy.__name__ = func.__name__
     funcopy.__doc__ = func.__doc__
+    try:
+        funcopy.__text_signature__ = func.__text_signature__
+    except AttributeError:
+        pass
     # we explicitly don't copy func.__dict__ into this copy as it would
     # expose original attributes that should be mocked
-    funcopy.__module__ = func.__module__
-    funcopy.__defaults__ = func.__defaults__
-    funcopy.__kwdefaults__ = func.__kwdefaults__
+    try:
+        funcopy.__module__ = func.__module__
+    except AttributeError:
+        pass
+    try:
+        funcopy.__defaults__ = func.__defaults__
+    except AttributeError:
+        pass
+    try:
+        funcopy.__kwdefaults__ = func.__kwdefaults__
+    except AttributeError:
+        pass
 
 
 def _callable(obj):