async def test_promise_cancellation_after_result(self):
p = Promise()
counter = Counter()
p.cancel()
with self.assertRaises(CancelledError):
await (p.then(lambda x: counter.update(["then"])).catch(
lambda exc: counter.update(["catch"])).lastly(
lambda: counter.update(["lastly"])))
self.assertTrue(p.done())
self.assertTrue(p.cancelled())
self.assertEqual(counter["then"], 0)
self.assertEqual(counter["catch"], 0)
self.assertEqual(counter["lastly"], 0)
async def test_promise_cancelled(self):
b = False
async def a():
nonlocal b
b = True
p = Promise()
lp = p.lastly(a)
p.cancel()
with self.assertRaises(CancelledError):
await p
with self.assertRaises(CancelledError):
await lp
self.assertFalse(b)
def test_cancel_differences_between_promise_and_future(self):
promise = Promise(self.fut)
promise.resolve(None)
with self.assertRaises(InvalidStateError):
self.fut.set_result(None)
with self.assertRaises(InvalidStateError):
self.fut.set_exception(Exception())
self.assertFalse(self.fut.cancel())
self.assertFalse(self.fut.cancelled())
self.assertTrue(promise.cancel())
self.assertTrue(promise.cancelled())
async def test_cancellation(self):
promise = Promise(self.fut)
promise.cancel()
self.assertAsyncRaises(CancelledError, self.fut)
self.assertAsyncRaises(CancelledError, promise)