From eed8c51db6c3fccfe634b324ae33ea156f906b75 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Fri, 28 Apr 2017 19:17:26 +0300 Subject: [PATCH 1/2] [3.5] bpo-30197: Enhance functions swap_attr() and swap_item() in test.support. (#1341) 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 d1a1def7bf221b04dcf3fc3a67aa19aa2f622f83) --- Lib/test/support/__init__.py | 16 ++++++++++++---- Lib/test/test_support.py | 29 +++++++++++++++++++++++------ Lib/test/test_tempfile.py | 5 ++--- Misc/NEWS | 6 ++++++ 4 files changed, 43 insertions(+), 13 deletions(-) diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py index a5aba3114370ee..a9f8fd5b3d7449 100644 --- a/Lib/test/support/__init__.py +++ b/Lib/test/support/__init__.py @@ -2073,12 +2073,15 @@ def swap_attr(obj, attr, new_val): restoring the old value at the end of the block. If `attr` doesn't exist on `obj`, it will be created and then deleted at the end of the block. + + The old value (or None if it doesn't exist) will be assigned to the + target of the "as" clause, if there is one. """ if hasattr(obj, attr): real_val = getattr(obj, attr) setattr(obj, attr, new_val) try: - yield + yield real_val finally: setattr(obj, attr, real_val) else: @@ -2086,7 +2089,8 @@ def swap_attr(obj, attr, new_val): try: yield finally: - delattr(obj, attr) + if hasattr(obj, attr): + delattr(obj, attr) @contextlib.contextmanager def swap_item(obj, item, new_val): @@ -2100,12 +2104,15 @@ def swap_item(obj, item, new_val): restoring the old value at the end of the block. If `item` doesn't exist on `obj`, it will be created and then deleted at the end of the block. + + The old value (or None if it doesn't exist) will be assigned to the + target of the "as" clause, if there is one. """ if item in obj: real_val = obj[item] obj[item] = new_val try: - yield + yield real_val finally: obj[item] = real_val else: @@ -2113,7 +2120,8 @@ def swap_item(obj, item, new_val): try: yield finally: - del obj[item] + if item in obj: + del obj[item] def strip_python_stderr(stderr): """Strip the stderr of a Python process from potential debug output diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py index 5e0f990e400045..70137e1a0be223 100644 --- a/Lib/test/test_support.py +++ b/Lib/test/test_support.py @@ -283,17 +283,34 @@ def test_python_is_optimized(self): 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 diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py index 51df1ecd7d18e6..d0cf04b0cb67ca 100644 --- a/Lib/test/test_tempfile.py +++ b/Lib/test/test_tempfile.py @@ -273,13 +273,12 @@ def raise_OSError(*args, **kwargs): tempfile._get_default_tempdir() self.assertEqual(os.listdir(our_temp_directory), []) - open = io.open def bad_writer(*args, **kwargs): - fp = open(*args, **kwargs) + fp = orig_open(*args, **kwargs) fp.write = raise_OSError return fp - with support.swap_attr(io, "open", bad_writer): + with support.swap_attr(io, "open", bad_writer) as orig_open: # test again with failing write() with self.assertRaises(FileNotFoundError): tempfile._get_default_tempdir() diff --git a/Misc/NEWS b/Misc/NEWS index d9494c13b3c96b..4c90aa83dfb0da 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -199,6 +199,12 @@ Build Tests ----- +- bpo-30197: Enhanced functions swap_attr() and swap_item() in the + test.support module. 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. + - Issue #29571: to match the behaviour of the ``re.LOCALE`` flag, test_re.test_locale_flag now uses ``locale.getpreferredencoding(False)`` to determine the candidate encoding for the test regex (allowing it to correctly From c2b218b57de24b3bd678aee3cc74770527c5ea77 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Fri, 28 Apr 2017 19:34:04 +0300 Subject: [PATCH 2/2] [3.5] bpo-30197: Enhance functions swap_attr() and swap_item() in test.support. (GH-1341) * bpo-30197: Enhance functions swap_attr() and swap_item() in test.support. 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. * Update docstrings.. (cherry picked from commit d1a1def7bf221b04dcf3fc3a67aa19aa2f622f83)