bpo-36871: Ensure method signature is used when asserting mock calls to a method (GH13261)

* Fix call_matcher for mock when using methods

* Add NEWS entry

* Use None check and convert doctest to unittest

* Use better name for mock in tests. Handle _SpecState when the attribute was not accessed and add tests.

* Use reset_mock instead of reinitialization. Change inner class constructor signature for check

* Reword comment regarding call object lookup logic

Lib/unittest/test/testmock/testmock.py

@@ -1347,6 +1347,54 @@ class MockTest(unittest.TestCase):
                         )
 
 
+    def test_assert_has_calls_nested_spec(self):
+        class Something:
+
+            def __init__(self): pass
+            def meth(self, a, b, c, d=None): pass
+
+            class Foo:
+
+                def __init__(self, a): pass
+                def meth1(self, a, b): pass
+
+        mock_class = create_autospec(Something)
+
+        for m in [mock_class, mock_class()]:
+            m.meth(1, 2, 3, d=1)
+            m.assert_has_calls([call.meth(1, 2, 3, d=1)])
+            m.assert_has_calls([call.meth(1, 2, 3, 1)])
+
+        mock_class.reset_mock()
+
+        for m in [mock_class, mock_class()]:
+            self.assertRaises(AssertionError, m.assert_has_calls, [call.Foo()])
+            m.Foo(1).meth1(1, 2)
+            m.assert_has_calls([call.Foo(1), call.Foo(1).meth1(1, 2)])
+            m.Foo.assert_has_calls([call(1), call().meth1(1, 2)])
+
+        mock_class.reset_mock()
+
+        invalid_calls = [call.meth(1),
+                         call.non_existent(1),
+                         call.Foo().non_existent(1),
+                         call.Foo().meth(1, 2, 3, 4)]
+
+        for kall in invalid_calls:
+            self.assertRaises(AssertionError,
+                              mock_class.assert_has_calls,
+                              [kall]
+            )
+
+
+    def test_assert_has_calls_nested_without_spec(self):
+        m = MagicMock()
+        m().foo().bar().baz()
+        m.one().two().three()
+        calls = call.one().two().three().call_list()
+        m.assert_has_calls(calls)
+
+
     def test_assert_has_calls_with_function_spec(self):
         def f(a, b, c, d=None): pass