Document and test the resolution of issue 3445 (tolerate missing attributes in functools.update_wrapper, previously implemented as a side effect of the __annotations__ copying patch) and implement issue 9567 (add a __wrapped__ attribute when using update_wrapper)
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index 2b6da64..211ef18 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -194,6 +194,7 @@
def test_default_update(self):
wrapper, f = self._default_update()
self.check_wrapper(wrapper, f)
+ self.assertIs(wrapper.__wrapped__, f)
self.assertEqual(wrapper.__name__, 'f')
self.assertEqual(wrapper.attr, 'This is also a test')
self.assertEqual(wrapper.__annotations__['a'], 'This is a new annotation')
@@ -236,6 +237,28 @@
self.assertEqual(wrapper.attr, 'This is a different test')
self.assertEqual(wrapper.dict_attr, f.dict_attr)
+ def test_missing_attributes(self):
+ def f():
+ pass
+ def wrapper():
+ pass
+ wrapper.dict_attr = {}
+ assign = ('attr',)
+ update = ('dict_attr',)
+ # Missing attributes on wrapped object are ignored
+ functools.update_wrapper(wrapper, f, assign, update)
+ self.assertNotIn('attr', wrapper.__dict__)
+ self.assertEqual(wrapper.dict_attr, {})
+ # Wrapper must have expected attributes for updating
+ del wrapper.dict_attr
+ with self.assertRaises(AttributeError):
+ functools.update_wrapper(wrapper, f, assign, update)
+ wrapper.dict_attr = 1
+ with self.assertRaises(AttributeError):
+ functools.update_wrapper(wrapper, f, assign, update)
+
+ @unittest.skipIf(sys.flags.optimize >= 2,
+ "Docstrings are omitted with -O2 and above")
def test_builtin_update(self):
# Test for bug #1576241
def wrapper():
@@ -495,6 +518,12 @@
self.assertEqual(f.hits, 0)
self.assertEqual(f.misses, 1)
+ # Test bypassing the cache
+ self.assertIs(f.__wrapped__, orig)
+ f.__wrapped__(x, y)
+ self.assertEqual(f.hits, 0)
+ self.assertEqual(f.misses, 1)
+
# test size zero (which means "never-cache")
@functools.lru_cache(0)
def f():