bpo-35226: Fix equality for nested unittest.mock.call objects. (#10555)

Also refactor the call recording imolementation and add some notes
about its limitations.

2 files changed, 22 insertions, 0 deletions

diff --git a/Doc/library/unittest.mock-examples.rst b/Doc/library/unittest.mock-examples.rst
index 60db4c2..16690f3 100644
--- a/Doc/library/unittest.mock-examples.rst
+++ b/Doc/library/unittest.mock-examples.rst
@@ -166,6 +166,15 @@ You use the :data:`call` object to construct lists for comparing with
     >>> mock.mock_calls == expected
     True
 
+However, parameters to calls that return mocks are not recorded, which means it is not
+possible to track nested calls where the parameters used to create ancestors are important:
+
+    >>> m = Mock()
+    >>> m.factory(important=True).deliver()
+    <Mock name='mock.factory().deliver()' id='...'>
+    >>> m.mock_calls[-1] == call.factory(important=False).deliver()
+    True
+
 
 Setting Return Values and Attributes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst
index 0ae2954..bfab00e 100644
--- a/Doc/library/unittest.mock.rst
+++ b/Doc/library/unittest.mock.rst
@@ -702,6 +702,19 @@ the *new_callable* argument to :func:`patch`.
         unpacked as tuples to get at the individual arguments. See
         :ref:`calls as tuples <calls-as-tuples>`.
 
+        .. note::
+
+            The way :attr:`mock_calls` are recorded means that where nested
+            calls are made, the parameters of ancestor calls are not recorded
+            and so will always compare equal:
+
+                >>> mock = MagicMock()
+                >>> mock.top(a=3).bottom()
+                <MagicMock name='mock.top().bottom()' id='...'>
+                >>> mock.mock_calls
+                [call.top(a=3), call.top().bottom()]
+                >>> mock.mock_calls[-1] == call.top(a=-1).bottom()
+                True
 
     .. attribute:: __class__