[3.6] bpo-30197: Enhance functions swap_attr() and swap_item() in test.support. (GH-1341) (#1345)

They now work when delete replaced attribute or item inside the with
statement.  The old value of the attribute or item (or None if it doesn't
exist) now will be assigned to the target of the "as" clause, if there is
one.

(cherry picked from commit d1a1def7bf)
This commit is contained in:
Serhiy Storchaka 2017-04-28 20:05:05 +03:00 committed by GitHub
parent e005dd9a6d
commit 712114b3f9
4 changed files with 46 additions and 13 deletions

View file

@ -282,17 +282,34 @@ class TestSupport(unittest.TestCase):
def test_swap_attr(self):
class Obj:
x = 1
pass
obj = Obj()
with support.swap_attr(obj, "x", 5):
obj.x = 1
with support.swap_attr(obj, "x", 5) as x:
self.assertEqual(obj.x, 5)
self.assertEqual(x, 1)
self.assertEqual(obj.x, 1)
with support.swap_attr(obj, "y", 5) as y:
self.assertEqual(obj.y, 5)
self.assertIsNone(y)
self.assertFalse(hasattr(obj, 'y'))
with support.swap_attr(obj, "y", 5):
del obj.y
self.assertFalse(hasattr(obj, 'y'))
def test_swap_item(self):
D = {"item":1}
with support.swap_item(D, "item", 5):
self.assertEqual(D["item"], 5)
self.assertEqual(D["item"], 1)
D = {"x":1}
with support.swap_item(D, "x", 5) as x:
self.assertEqual(D["x"], 5)
self.assertEqual(x, 1)
self.assertEqual(D["x"], 1)
with support.swap_item(D, "y", 5) as y:
self.assertEqual(D["y"], 5)
self.assertIsNone(y)
self.assertNotIn("y", D)
with support.swap_item(D, "y", 5):
del D["y"]
self.assertNotIn("y", D)
class RefClass:
attribute1 = None