tests.py

importunittest
fromucontextlibimportcontextmanager


classContextManagerTestCase(unittest.TestCase):
defsetUp(self):
self._history= []

@contextmanager
defmanager(x):
self._history.append("start")
try:
yieldx
finally:
self._history.append("finish")

self._manager=manager

deftest_context_manager(self):
withself._manager(123) asx:
self.assertEqual(x, 123)
self.assertEqual(self._history, ["start", "finish"])

deftest_context_manager_on_error(self):
exc=Exception()
try:
withself._manager(123):
raiseexc
exceptExceptionase:
self.assertEqual(exc, e)
self.assertEqual(self._history, ["start", "finish"])


if__name__=="__main__":
unittest.main()