def test_swap_item(self):
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)
def test_cannot_replace_builtins_dict_between_calls(self):
def foo():
return len([1, 2, 3])
self.configure_func(foo)
self.assertEqual(foo(), 3)
with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
self.assertEqual(foo(), 3)
def test_globals_shadow_builtins(self):
# Modify globals() to shadow an entry in builtins.
def foo():
return len([1, 2, 3])
self.configure_func(foo)
self.assertEqual(foo(), 3)
with swap_item(globals(), "len", lambda x: 7):
self.assertEqual(foo(), 7)
def test_cannot_replace_builtins_dict_while_active(self):
def foo():
x = range(3)
yield len(x)
yield len(x)
self.configure_func(foo)
g = foo()
self.assertEqual(next(g), 3)
with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
self.assertEqual(next(g), 3)
def test_override_builtin(self):
# Test that overriding builtins.__import__ can bypass sys.modules.
import os
def foo():
import os
return os
self.assertEqual(foo(), os) # Quick sanity check.
with swap_attr(builtins, "__import__", lambda *x: 5):
self.assertEqual(foo(), 5)
# Test what happens when we shadow __import__ in globals(); this
# currently does not impact the import process, but if this changes,
# other code will need to change, so keep this test as a tripwire.
with swap_item(globals(), "__import__", lambda *x: 5):
self.assertEqual(foo(), os)
def copy(self, obj, proto):
with support.swap_item(sys.modules, 'operator', self.module):
pickled = pickle.dumps(obj, proto)
with support.swap_item(sys.modules, 'operator', self.module2):
return pickle.loads(pickled)