mirror of
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844 lines
26 KiB
Python
844 lines
26 KiB
Python
"""Unit tests for contextlib.py, and other context managers."""
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import io
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import sys
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import tempfile
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import unittest
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from contextlib import * # Tests __all__
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from test import support
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try:
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import threading
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except ImportError:
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threading = None
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class ContextManagerTestCase(unittest.TestCase):
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def test_contextmanager_plain(self):
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state = []
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@contextmanager
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def woohoo():
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state.append(1)
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yield 42
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state.append(999)
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with woohoo() as x:
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self.assertEqual(state, [1])
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self.assertEqual(x, 42)
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state.append(x)
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self.assertEqual(state, [1, 42, 999])
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def test_contextmanager_finally(self):
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state = []
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@contextmanager
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def woohoo():
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state.append(1)
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try:
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yield 42
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finally:
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state.append(999)
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with self.assertRaises(ZeroDivisionError):
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with woohoo() as x:
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self.assertEqual(state, [1])
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self.assertEqual(x, 42)
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state.append(x)
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raise ZeroDivisionError()
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self.assertEqual(state, [1, 42, 999])
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def test_contextmanager_no_reraise(self):
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@contextmanager
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def whee():
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yield
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ctx = whee()
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ctx.__enter__()
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# Calling __exit__ should not result in an exception
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self.assertFalse(ctx.__exit__(TypeError, TypeError("foo"), None))
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def test_contextmanager_trap_yield_after_throw(self):
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@contextmanager
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def whoo():
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try:
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yield
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except:
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yield
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ctx = whoo()
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ctx.__enter__()
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self.assertRaises(
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RuntimeError, ctx.__exit__, TypeError, TypeError("foo"), None
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)
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def test_contextmanager_except(self):
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state = []
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@contextmanager
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def woohoo():
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state.append(1)
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try:
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yield 42
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except ZeroDivisionError as e:
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state.append(e.args[0])
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self.assertEqual(state, [1, 42, 999])
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with woohoo() as x:
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self.assertEqual(state, [1])
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self.assertEqual(x, 42)
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state.append(x)
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raise ZeroDivisionError(999)
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self.assertEqual(state, [1, 42, 999])
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def _create_contextmanager_attribs(self):
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def attribs(**kw):
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def decorate(func):
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for k,v in kw.items():
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setattr(func,k,v)
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return func
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return decorate
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@contextmanager
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@attribs(foo='bar')
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def baz(spam):
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"""Whee!"""
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return baz
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def test_contextmanager_attribs(self):
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baz = self._create_contextmanager_attribs()
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self.assertEqual(baz.__name__,'baz')
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self.assertEqual(baz.foo, 'bar')
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@support.requires_docstrings
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def test_contextmanager_doc_attrib(self):
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baz = self._create_contextmanager_attribs()
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self.assertEqual(baz.__doc__, "Whee!")
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@support.requires_docstrings
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def test_instance_docstring_given_cm_docstring(self):
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baz = self._create_contextmanager_attribs()(None)
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self.assertEqual(baz.__doc__, "Whee!")
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class ClosingTestCase(unittest.TestCase):
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@support.requires_docstrings
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def test_instance_docs(self):
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# Issue 19330: ensure context manager instances have good docstrings
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cm_docstring = closing.__doc__
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obj = closing(None)
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self.assertEqual(obj.__doc__, cm_docstring)
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def test_closing(self):
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state = []
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class C:
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def close(self):
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state.append(1)
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x = C()
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self.assertEqual(state, [])
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with closing(x) as y:
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self.assertEqual(x, y)
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self.assertEqual(state, [1])
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def test_closing_error(self):
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state = []
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class C:
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def close(self):
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state.append(1)
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x = C()
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self.assertEqual(state, [])
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with self.assertRaises(ZeroDivisionError):
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with closing(x) as y:
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self.assertEqual(x, y)
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1 / 0
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self.assertEqual(state, [1])
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class FileContextTestCase(unittest.TestCase):
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def testWithOpen(self):
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tfn = tempfile.mktemp()
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try:
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f = None
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with open(tfn, "w") as f:
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self.assertFalse(f.closed)
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f.write("Booh\n")
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self.assertTrue(f.closed)
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f = None
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with self.assertRaises(ZeroDivisionError):
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with open(tfn, "r") as f:
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self.assertFalse(f.closed)
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self.assertEqual(f.read(), "Booh\n")
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1 / 0
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self.assertTrue(f.closed)
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finally:
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support.unlink(tfn)
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@unittest.skipUnless(threading, 'Threading required for this test.')
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class LockContextTestCase(unittest.TestCase):
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def boilerPlate(self, lock, locked):
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self.assertFalse(locked())
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with lock:
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self.assertTrue(locked())
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self.assertFalse(locked())
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with self.assertRaises(ZeroDivisionError):
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with lock:
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self.assertTrue(locked())
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1 / 0
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self.assertFalse(locked())
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def testWithLock(self):
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lock = threading.Lock()
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self.boilerPlate(lock, lock.locked)
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def testWithRLock(self):
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lock = threading.RLock()
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self.boilerPlate(lock, lock._is_owned)
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def testWithCondition(self):
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lock = threading.Condition()
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def locked():
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return lock._is_owned()
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self.boilerPlate(lock, locked)
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def testWithSemaphore(self):
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lock = threading.Semaphore()
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def locked():
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if lock.acquire(False):
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lock.release()
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return False
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else:
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return True
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self.boilerPlate(lock, locked)
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def testWithBoundedSemaphore(self):
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lock = threading.BoundedSemaphore()
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def locked():
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if lock.acquire(False):
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lock.release()
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return False
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else:
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return True
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self.boilerPlate(lock, locked)
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class mycontext(ContextDecorator):
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"""Example decoration-compatible context manager for testing"""
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started = False
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exc = None
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catch = False
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def __enter__(self):
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self.started = True
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return self
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def __exit__(self, *exc):
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self.exc = exc
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return self.catch
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class TestContextDecorator(unittest.TestCase):
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@support.requires_docstrings
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def test_instance_docs(self):
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# Issue 19330: ensure context manager instances have good docstrings
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cm_docstring = mycontext.__doc__
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obj = mycontext()
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self.assertEqual(obj.__doc__, cm_docstring)
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def test_contextdecorator(self):
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context = mycontext()
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with context as result:
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self.assertIs(result, context)
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self.assertTrue(context.started)
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self.assertEqual(context.exc, (None, None, None))
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def test_contextdecorator_with_exception(self):
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context = mycontext()
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with self.assertRaisesRegex(NameError, 'foo'):
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with context:
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raise NameError('foo')
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self.assertIsNotNone(context.exc)
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self.assertIs(context.exc[0], NameError)
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context = mycontext()
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context.catch = True
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with context:
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raise NameError('foo')
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self.assertIsNotNone(context.exc)
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self.assertIs(context.exc[0], NameError)
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def test_decorator(self):
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context = mycontext()
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@context
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def test():
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self.assertIsNone(context.exc)
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self.assertTrue(context.started)
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test()
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self.assertEqual(context.exc, (None, None, None))
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def test_decorator_with_exception(self):
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context = mycontext()
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@context
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def test():
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self.assertIsNone(context.exc)
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self.assertTrue(context.started)
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raise NameError('foo')
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with self.assertRaisesRegex(NameError, 'foo'):
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test()
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self.assertIsNotNone(context.exc)
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self.assertIs(context.exc[0], NameError)
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def test_decorating_method(self):
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context = mycontext()
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class Test(object):
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@context
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def method(self, a, b, c=None):
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self.a = a
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self.b = b
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self.c = c
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# these tests are for argument passing when used as a decorator
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test = Test()
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test.method(1, 2)
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self.assertEqual(test.a, 1)
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self.assertEqual(test.b, 2)
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self.assertEqual(test.c, None)
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test = Test()
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test.method('a', 'b', 'c')
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self.assertEqual(test.a, 'a')
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self.assertEqual(test.b, 'b')
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self.assertEqual(test.c, 'c')
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test = Test()
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test.method(a=1, b=2)
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self.assertEqual(test.a, 1)
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self.assertEqual(test.b, 2)
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def test_typo_enter(self):
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class mycontext(ContextDecorator):
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def __unter__(self):
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pass
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def __exit__(self, *exc):
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pass
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with self.assertRaises(AttributeError):
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with mycontext():
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pass
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def test_typo_exit(self):
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class mycontext(ContextDecorator):
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def __enter__(self):
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pass
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def __uxit__(self, *exc):
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pass
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with self.assertRaises(AttributeError):
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with mycontext():
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pass
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def test_contextdecorator_as_mixin(self):
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class somecontext(object):
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started = False
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exc = None
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def __enter__(self):
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self.started = True
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return self
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def __exit__(self, *exc):
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self.exc = exc
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class mycontext(somecontext, ContextDecorator):
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pass
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context = mycontext()
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@context
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def test():
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self.assertIsNone(context.exc)
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self.assertTrue(context.started)
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test()
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self.assertEqual(context.exc, (None, None, None))
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def test_contextmanager_as_decorator(self):
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@contextmanager
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def woohoo(y):
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state.append(y)
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yield
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state.append(999)
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state = []
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@woohoo(1)
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def test(x):
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self.assertEqual(state, [1])
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state.append(x)
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test('something')
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self.assertEqual(state, [1, 'something', 999])
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# Issue #11647: Ensure the decorated function is 'reusable'
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state = []
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test('something else')
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self.assertEqual(state, [1, 'something else', 999])
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class TestExitStack(unittest.TestCase):
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@support.requires_docstrings
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def test_instance_docs(self):
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# Issue 19330: ensure context manager instances have good docstrings
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cm_docstring = ExitStack.__doc__
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obj = ExitStack()
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self.assertEqual(obj.__doc__, cm_docstring)
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def test_no_resources(self):
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with ExitStack():
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pass
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def test_callback(self):
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expected = [
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((), {}),
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((1,), {}),
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((1,2), {}),
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((), dict(example=1)),
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((1,), dict(example=1)),
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((1,2), dict(example=1)),
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]
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result = []
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def _exit(*args, **kwds):
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"""Test metadata propagation"""
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result.append((args, kwds))
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with ExitStack() as stack:
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for args, kwds in reversed(expected):
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if args and kwds:
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f = stack.callback(_exit, *args, **kwds)
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elif args:
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f = stack.callback(_exit, *args)
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elif kwds:
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f = stack.callback(_exit, **kwds)
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else:
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f = stack.callback(_exit)
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self.assertIs(f, _exit)
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for wrapper in stack._exit_callbacks:
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self.assertIs(wrapper.__wrapped__, _exit)
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self.assertNotEqual(wrapper.__name__, _exit.__name__)
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self.assertIsNone(wrapper.__doc__, _exit.__doc__)
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self.assertEqual(result, expected)
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def test_push(self):
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exc_raised = ZeroDivisionError
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def _expect_exc(exc_type, exc, exc_tb):
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self.assertIs(exc_type, exc_raised)
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def _suppress_exc(*exc_details):
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return True
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def _expect_ok(exc_type, exc, exc_tb):
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self.assertIsNone(exc_type)
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self.assertIsNone(exc)
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self.assertIsNone(exc_tb)
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class ExitCM(object):
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def __init__(self, check_exc):
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self.check_exc = check_exc
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def __enter__(self):
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self.fail("Should not be called!")
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def __exit__(self, *exc_details):
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self.check_exc(*exc_details)
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with ExitStack() as stack:
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stack.push(_expect_ok)
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self.assertIs(stack._exit_callbacks[-1], _expect_ok)
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cm = ExitCM(_expect_ok)
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stack.push(cm)
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self.assertIs(stack._exit_callbacks[-1].__self__, cm)
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stack.push(_suppress_exc)
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self.assertIs(stack._exit_callbacks[-1], _suppress_exc)
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cm = ExitCM(_expect_exc)
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stack.push(cm)
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self.assertIs(stack._exit_callbacks[-1].__self__, cm)
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stack.push(_expect_exc)
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self.assertIs(stack._exit_callbacks[-1], _expect_exc)
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stack.push(_expect_exc)
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self.assertIs(stack._exit_callbacks[-1], _expect_exc)
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1/0
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def test_enter_context(self):
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class TestCM(object):
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def __enter__(self):
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result.append(1)
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def __exit__(self, *exc_details):
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result.append(3)
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result = []
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cm = TestCM()
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with ExitStack() as stack:
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@stack.callback # Registered first => cleaned up last
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def _exit():
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result.append(4)
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self.assertIsNotNone(_exit)
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stack.enter_context(cm)
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self.assertIs(stack._exit_callbacks[-1].__self__, cm)
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result.append(2)
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self.assertEqual(result, [1, 2, 3, 4])
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def test_close(self):
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result = []
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with ExitStack() as stack:
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@stack.callback
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def _exit():
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result.append(1)
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self.assertIsNotNone(_exit)
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stack.close()
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result.append(2)
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self.assertEqual(result, [1, 2])
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def test_pop_all(self):
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result = []
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with ExitStack() as stack:
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@stack.callback
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def _exit():
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result.append(3)
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self.assertIsNotNone(_exit)
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new_stack = stack.pop_all()
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result.append(1)
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result.append(2)
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new_stack.close()
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self.assertEqual(result, [1, 2, 3])
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def test_exit_raise(self):
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with self.assertRaises(ZeroDivisionError):
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with ExitStack() as stack:
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stack.push(lambda *exc: False)
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1/0
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def test_exit_suppress(self):
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with ExitStack() as stack:
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stack.push(lambda *exc: True)
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1/0
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def test_exit_exception_chaining_reference(self):
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# Sanity check to make sure that ExitStack chaining matches
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# actual nested with statements
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class RaiseExc:
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def __init__(self, exc):
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self.exc = exc
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def __enter__(self):
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return self
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def __exit__(self, *exc_details):
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raise self.exc
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class RaiseExcWithContext:
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def __init__(self, outer, inner):
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self.outer = outer
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self.inner = inner
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def __enter__(self):
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return self
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def __exit__(self, *exc_details):
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try:
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raise self.inner
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except:
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raise self.outer
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class SuppressExc:
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def __enter__(self):
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return self
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def __exit__(self, *exc_details):
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type(self).saved_details = exc_details
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return True
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try:
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with RaiseExc(IndexError):
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with RaiseExcWithContext(KeyError, AttributeError):
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with SuppressExc():
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with RaiseExc(ValueError):
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1 / 0
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except IndexError as exc:
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self.assertIsInstance(exc.__context__, KeyError)
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self.assertIsInstance(exc.__context__.__context__, AttributeError)
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# Inner exceptions were suppressed
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self.assertIsNone(exc.__context__.__context__.__context__)
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else:
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self.fail("Expected IndexError, but no exception was raised")
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# Check the inner exceptions
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inner_exc = SuppressExc.saved_details[1]
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self.assertIsInstance(inner_exc, ValueError)
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self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
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def test_exit_exception_chaining(self):
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# Ensure exception chaining matches the reference behaviour
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def raise_exc(exc):
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raise exc
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|
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saved_details = None
|
|
def suppress_exc(*exc_details):
|
|
nonlocal saved_details
|
|
saved_details = exc_details
|
|
return True
|
|
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.callback(raise_exc, IndexError)
|
|
stack.callback(raise_exc, KeyError)
|
|
stack.callback(raise_exc, AttributeError)
|
|
stack.push(suppress_exc)
|
|
stack.callback(raise_exc, ValueError)
|
|
1 / 0
|
|
except IndexError as exc:
|
|
self.assertIsInstance(exc.__context__, KeyError)
|
|
self.assertIsInstance(exc.__context__.__context__, AttributeError)
|
|
# Inner exceptions were suppressed
|
|
self.assertIsNone(exc.__context__.__context__.__context__)
|
|
else:
|
|
self.fail("Expected IndexError, but no exception was raised")
|
|
# Check the inner exceptions
|
|
inner_exc = saved_details[1]
|
|
self.assertIsInstance(inner_exc, ValueError)
|
|
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
|
|
|
|
def test_exit_exception_non_suppressing(self):
|
|
# http://bugs.python.org/issue19092
|
|
def raise_exc(exc):
|
|
raise exc
|
|
|
|
def suppress_exc(*exc_details):
|
|
return True
|
|
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.callback(lambda: None)
|
|
stack.callback(raise_exc, IndexError)
|
|
except Exception as exc:
|
|
self.assertIsInstance(exc, IndexError)
|
|
else:
|
|
self.fail("Expected IndexError, but no exception was raised")
|
|
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.callback(raise_exc, KeyError)
|
|
stack.push(suppress_exc)
|
|
stack.callback(raise_exc, IndexError)
|
|
except Exception as exc:
|
|
self.assertIsInstance(exc, KeyError)
|
|
else:
|
|
self.fail("Expected KeyError, but no exception was raised")
|
|
|
|
def test_exit_exception_with_correct_context(self):
|
|
# http://bugs.python.org/issue20317
|
|
@contextmanager
|
|
def gets_the_context_right(exc):
|
|
try:
|
|
yield
|
|
finally:
|
|
raise exc
|
|
|
|
exc1 = Exception(1)
|
|
exc2 = Exception(2)
|
|
exc3 = Exception(3)
|
|
exc4 = Exception(4)
|
|
|
|
# The contextmanager already fixes the context, so prior to the
|
|
# fix, ExitStack would try to fix it *again* and get into an
|
|
# infinite self-referential loop
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.enter_context(gets_the_context_right(exc4))
|
|
stack.enter_context(gets_the_context_right(exc3))
|
|
stack.enter_context(gets_the_context_right(exc2))
|
|
raise exc1
|
|
except Exception as exc:
|
|
self.assertIs(exc, exc4)
|
|
self.assertIs(exc.__context__, exc3)
|
|
self.assertIs(exc.__context__.__context__, exc2)
|
|
self.assertIs(exc.__context__.__context__.__context__, exc1)
|
|
self.assertIsNone(
|
|
exc.__context__.__context__.__context__.__context__)
|
|
|
|
def test_exit_exception_with_existing_context(self):
|
|
# Addresses a lack of test coverage discovered after checking in a
|
|
# fix for issue 20317 that still contained debugging code.
|
|
def raise_nested(inner_exc, outer_exc):
|
|
try:
|
|
raise inner_exc
|
|
finally:
|
|
raise outer_exc
|
|
exc1 = Exception(1)
|
|
exc2 = Exception(2)
|
|
exc3 = Exception(3)
|
|
exc4 = Exception(4)
|
|
exc5 = Exception(5)
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.callback(raise_nested, exc4, exc5)
|
|
stack.callback(raise_nested, exc2, exc3)
|
|
raise exc1
|
|
except Exception as exc:
|
|
self.assertIs(exc, exc5)
|
|
self.assertIs(exc.__context__, exc4)
|
|
self.assertIs(exc.__context__.__context__, exc3)
|
|
self.assertIs(exc.__context__.__context__.__context__, exc2)
|
|
self.assertIs(
|
|
exc.__context__.__context__.__context__.__context__, exc1)
|
|
self.assertIsNone(
|
|
exc.__context__.__context__.__context__.__context__.__context__)
|
|
|
|
|
|
|
|
def test_body_exception_suppress(self):
|
|
def suppress_exc(*exc_details):
|
|
return True
|
|
try:
|
|
with ExitStack() as stack:
|
|
stack.push(suppress_exc)
|
|
1/0
|
|
except IndexError as exc:
|
|
self.fail("Expected no exception, got IndexError")
|
|
|
|
def test_exit_exception_chaining_suppress(self):
|
|
with ExitStack() as stack:
|
|
stack.push(lambda *exc: True)
|
|
stack.push(lambda *exc: 1/0)
|
|
stack.push(lambda *exc: {}[1])
|
|
|
|
def test_excessive_nesting(self):
|
|
# The original implementation would die with RecursionError here
|
|
with ExitStack() as stack:
|
|
for i in range(10000):
|
|
stack.callback(int)
|
|
|
|
def test_instance_bypass(self):
|
|
class Example(object): pass
|
|
cm = Example()
|
|
cm.__exit__ = object()
|
|
stack = ExitStack()
|
|
self.assertRaises(AttributeError, stack.enter_context, cm)
|
|
stack.push(cm)
|
|
self.assertIs(stack._exit_callbacks[-1], cm)
|
|
|
|
|
|
class TestRedirectStream:
|
|
|
|
redirect_stream = None
|
|
orig_stream = None
|
|
|
|
@support.requires_docstrings
|
|
def test_instance_docs(self):
|
|
# Issue 19330: ensure context manager instances have good docstrings
|
|
cm_docstring = self.redirect_stream.__doc__
|
|
obj = self.redirect_stream(None)
|
|
self.assertEqual(obj.__doc__, cm_docstring)
|
|
|
|
def test_no_redirect_in_init(self):
|
|
orig_stdout = getattr(sys, self.orig_stream)
|
|
self.redirect_stream(None)
|
|
self.assertIs(getattr(sys, self.orig_stream), orig_stdout)
|
|
|
|
def test_redirect_to_string_io(self):
|
|
f = io.StringIO()
|
|
msg = "Consider an API like help(), which prints directly to stdout"
|
|
orig_stdout = getattr(sys, self.orig_stream)
|
|
with self.redirect_stream(f):
|
|
print(msg, file=getattr(sys, self.orig_stream))
|
|
self.assertIs(getattr(sys, self.orig_stream), orig_stdout)
|
|
s = f.getvalue().strip()
|
|
self.assertEqual(s, msg)
|
|
|
|
def test_enter_result_is_target(self):
|
|
f = io.StringIO()
|
|
with self.redirect_stream(f) as enter_result:
|
|
self.assertIs(enter_result, f)
|
|
|
|
def test_cm_is_reusable(self):
|
|
f = io.StringIO()
|
|
write_to_f = self.redirect_stream(f)
|
|
orig_stdout = getattr(sys, self.orig_stream)
|
|
with write_to_f:
|
|
print("Hello", end=" ", file=getattr(sys, self.orig_stream))
|
|
with write_to_f:
|
|
print("World!", file=getattr(sys, self.orig_stream))
|
|
self.assertIs(getattr(sys, self.orig_stream), orig_stdout)
|
|
s = f.getvalue()
|
|
self.assertEqual(s, "Hello World!\n")
|
|
|
|
def test_cm_is_reentrant(self):
|
|
f = io.StringIO()
|
|
write_to_f = self.redirect_stream(f)
|
|
orig_stdout = getattr(sys, self.orig_stream)
|
|
with write_to_f:
|
|
print("Hello", end=" ", file=getattr(sys, self.orig_stream))
|
|
with write_to_f:
|
|
print("World!", file=getattr(sys, self.orig_stream))
|
|
self.assertIs(getattr(sys, self.orig_stream), orig_stdout)
|
|
s = f.getvalue()
|
|
self.assertEqual(s, "Hello World!\n")
|
|
|
|
|
|
class TestRedirectStdout(TestRedirectStream, unittest.TestCase):
|
|
|
|
redirect_stream = redirect_stdout
|
|
orig_stream = "stdout"
|
|
|
|
|
|
class TestRedirectStderr(TestRedirectStream, unittest.TestCase):
|
|
|
|
redirect_stream = redirect_stderr
|
|
orig_stream = "stderr"
|
|
|
|
|
|
class TestSuppress(unittest.TestCase):
|
|
|
|
@support.requires_docstrings
|
|
def test_instance_docs(self):
|
|
# Issue 19330: ensure context manager instances have good docstrings
|
|
cm_docstring = suppress.__doc__
|
|
obj = suppress()
|
|
self.assertEqual(obj.__doc__, cm_docstring)
|
|
|
|
def test_no_result_from_enter(self):
|
|
with suppress(ValueError) as enter_result:
|
|
self.assertIsNone(enter_result)
|
|
|
|
def test_no_exception(self):
|
|
with suppress(ValueError):
|
|
self.assertEqual(pow(2, 5), 32)
|
|
|
|
def test_exact_exception(self):
|
|
with suppress(TypeError):
|
|
len(5)
|
|
|
|
def test_exception_hierarchy(self):
|
|
with suppress(LookupError):
|
|
'Hello'[50]
|
|
|
|
def test_other_exception(self):
|
|
with self.assertRaises(ZeroDivisionError):
|
|
with suppress(TypeError):
|
|
1/0
|
|
|
|
def test_no_args(self):
|
|
with self.assertRaises(ZeroDivisionError):
|
|
with suppress():
|
|
1/0
|
|
|
|
def test_multiple_exception_args(self):
|
|
with suppress(ZeroDivisionError, TypeError):
|
|
1/0
|
|
with suppress(ZeroDivisionError, TypeError):
|
|
len(5)
|
|
|
|
def test_cm_is_reentrant(self):
|
|
ignore_exceptions = suppress(Exception)
|
|
with ignore_exceptions:
|
|
pass
|
|
with ignore_exceptions:
|
|
len(5)
|
|
with ignore_exceptions:
|
|
1/0
|
|
with ignore_exceptions: # Check nested usage
|
|
len(5)
|
|
|
|
if __name__ == "__main__":
|
|
unittest.main()
|