Get mock coverage back to 100% (GH-18228)

* use the `: pass` and `: yield` patterns for code that isn't expected to ever be executed.

* The _Call items passed to _AnyComparer are only ever of length two, so assert instead of if/else

* fix typo

* Fix bug, where stop-without-start patching dict blows up with `TypeError: 'NoneType' object is not iterable`, highlighted by lack of coverage of an except branch.

* The fix for bpo-37972 means _Call.count and _Call.index are no longer needed.

* add coverage for calling next() on a mock_open with readline.return_value set.

* __aiter__ is defined on the Mock so the one on _AsyncIterator is never called.

1 files changed, 4 insertions, 13 deletions

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 37ea5c7..9e69298 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -1042,8 +1042,7 @@ class _AnyComparer(list):
     the left."""
     def __contains__(self, item):
         for _call in self:
-            if len(item) != len(_call):
-                continue
+            assert len(item) == len(_call)
             if all([
                 expected == actual
                 for expected, actual in zip(item, _call)
@@ -1856,7 +1855,8 @@ class _patch_dict(object):
 
     def __exit__(self, *args):
         """Unpatch the dict."""
-        self._unpatch_dict()
+        if self._original is not None:
+            self._unpatch_dict()
         return False
 
 
@@ -2168,7 +2168,7 @@ class AsyncMockMixin(Base):
         self.__dict__['__code__'] = code_mock
 
     async def _execute_mock_call(self, /, *args, **kwargs):
-        # This is nearly just like super(), except for sepcial handling
+        # This is nearly just like super(), except for special handling
         # of coroutines
 
         _call = self.call_args
@@ -2541,12 +2541,6 @@ class _Call(tuple):
         return tuple.__getattribute__(self, attr)
 
 
-    def count(self, /, *args, **kwargs):
-        return self.__getattr__('count')(*args, **kwargs)
-
-    def index(self, /, *args, **kwargs):
-        return self.__getattr__('index')(*args, **kwargs)
-
     def _get_call_arguments(self):
         if len(self) == 2:
             args, kwargs = self
@@ -2917,9 +2911,6 @@ class _AsyncIterator:
         code_mock.co_flags = inspect.CO_ITERABLE_COROUTINE
         self.__dict__['__code__'] = code_mock
 
-    def __aiter__(self):
-        return self
-
     async def __anext__(self):
         try:
             return next(self.iterator)