[Python-checkins] bpo-17185: Add __signature__ to mock that can be used by inspect for signature (GH11048)

[Chris Withers]

https://github.com/python/cpython/commit/f7fa62ef4422c9deee050a794fd8504640d9f8f4
commit: f7fa62ef4422c9deee050a794fd8504640d9f8f4
branch: master
author: Xtreak <tirkarthi at users.noreply.github.com>
committer: Chris Withers <chris at withers.org>
date: 2018-12-12T07:54:54Z
summary:

bpo-17185: Add __signature__ to mock that can be used by inspect for signature (GH11048)

* Fix partial and partial method signatures in mock

* Add more calls

* Add NEWS entry

* Use assertEquals and fix markup in NEWS

* Refactor branching and add markup reference for functools

* Revert partial object related changes and fix pr comments

files:
A Misc/NEWS.d/next/Library/2018-12-09-17-04-15.bpo-17185.SfSCJF.rst
M Lib/unittest/mock.py
M Lib/unittest/test/testmock/testhelpers.py

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 61ed80b976a7..38189c9aec2e 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -103,6 +103,7 @@ def checksig(_mock_self, *args, **kwargs):
         sig.bind(*args, **kwargs)
     _copy_func_details(func, checksig)
     type(mock)._mock_check_sig = checksig
+    type(mock).__signature__ = sig
 
 
 def _copy_func_details(func, funcopy):
@@ -172,11 +173,11 @@ def checksig(*args, **kwargs):
     return mock(*args, **kwargs)""" % name
     exec (src, context)
     funcopy = context[name]
-    _setup_func(funcopy, mock)
+    _setup_func(funcopy, mock, sig)
     return funcopy
 
 
-def _setup_func(funcopy, mock):
+def _setup_func(funcopy, mock, sig):
     funcopy.mock = mock
 
     # can't use isinstance with mocks
@@ -224,6 +225,7 @@ def reset_mock():
     funcopy.assert_called = assert_called
     funcopy.assert_not_called = assert_not_called
     funcopy.assert_called_once = assert_called_once
+    funcopy.__signature__ = sig
 
     mock._mock_delegate = funcopy
 
diff --git a/Lib/unittest/test/testmock/testhelpers.py b/Lib/unittest/test/testmock/testhelpers.py
index 9388311e3e25..745580ef79db 100644
--- a/Lib/unittest/test/testmock/testhelpers.py
+++ b/Lib/unittest/test/testmock/testhelpers.py
@@ -1,3 +1,4 @@
+import inspect
 import time
 import types
 import unittest
@@ -901,6 +902,35 @@ def __getattr__(self, attribute):
         self.assertFalse(hasattr(autospec, '__name__'))
 
 
+    def test_spec_inspect_signature(self):
+
+        def myfunc(x, y):
+            pass
+
+        mock = create_autospec(myfunc)
+        mock(1, 2)
+        mock(x=1, y=2)
+
+        self.assertEqual(inspect.getfullargspec(mock), inspect.getfullargspec(myfunc))
+        self.assertEqual(mock.mock_calls, [call(1, 2), call(x=1, y=2)])
+        self.assertRaises(TypeError, mock, 1)
+
+
+    def test_spec_inspect_signature_annotations(self):
+
+        def foo(a: int, b: int=10, *, c:int) -> int:
+            return a + b + c
+
+        mock = create_autospec(foo)
+        mock(1, 2, c=3)
+        mock(1, c=3)
+
+        self.assertEqual(inspect.getfullargspec(mock), inspect.getfullargspec(foo))
+        self.assertEqual(mock.mock_calls, [call(1, 2, c=3), call(1, c=3)])
+        self.assertRaises(TypeError, mock, 1)
+        self.assertRaises(TypeError, mock, 1, 2, 3, c=4)
+
+
 class TestCallList(unittest.TestCase):
 
     def test_args_list_contains_call_list(self):
diff --git a/Misc/NEWS.d/next/Library/2018-12-09-17-04-15.bpo-17185.SfSCJF.rst b/Misc/NEWS.d/next/Library/2018-12-09-17-04-15.bpo-17185.SfSCJF.rst
new file mode 100644
index 000000000000..311c6d2b0e4e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-12-09-17-04-15.bpo-17185.SfSCJF.rst
@@ -0,0 +1,2 @@
+Set ``__signature__`` on mock for :mod:`inspect` to get signature.
+Patch by Karthikeyan Singaravelan.