async def test_coro_resolve(self):
p = Promise(success_sleep(), loop=self.loop)
with self.assertRaisesRegex(RuntimeError, "Task does not support set_result operation"):
p.resolve(None)
self.assertEqual(await p, SUCCESS_RESULT)
async def test_resolution(self):
promise = Promise(self.fut)
promise.resolve(None)
result = await promise
self.assertIsNone(result)
self.assertEqual(await self.fut, result)
async def test_promise_of_a_promise(self):
p = Promise()
p2 = Promise(p)
p.resolve(0)
self.assertEqual(await p2.then(lambda x: 1 / x).catch(lambda exc: 0),
0)
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_promise_cancelled_2(self):
b = False
async def a():
nonlocal b
b = True
p = Promise()
lp = p.lastly(a)
p.resolve(10)
lp.cancel()
with self.assertRaises(CancelledError):
await lp
self.assertEqual(await p, 10)
self.assertFalse(b)
async def test_promise_chain_stack(self):
p = Promise()
self.assertEqual(len(p._stack), 1)
self.assertEqual(p._stack[0].line, "p = Promise()")
self.assertEqual(p._stack[0].lineno, 14)
c1_1 = p.lastly(lambda: 1)
self.assertEqual(len(c1_1._stack), 2)
self.assertEqual(c1_1._stack[0], p._stack[0])
self.assertEqual(c1_1._stack[1].line, "c1_1 = p.lastly(lambda: 1)")
self.assertEqual(c1_1._stack[1].lineno, 20)
c1_2 = c1_1.then(
lambda _:
"LongTextToPurposelyLargerThenTheCharacterLimitOfBlackWhichIsCurrently99"
)
self.assertEqual(len(c1_2._stack), 3)
self.assertEqual(c1_2._stack[0], p._stack[0])
self.assertEqual(c1_2._stack[1], c1_1._stack[1])
if sys.version_info >= (3, 8):
# Python 3.8 supposedly changed this behaviour...
self.assertEqual(c1_2._stack[2].line, "c1_2 = c1_1.then(")
self.assertEqual(c1_2._stack[2].lineno, 27)
else:
self.assertEqual(
c1_2._stack[2].line,
'lambda _: "LongTextToPurposelyLargerThenTheCharacterLimitOfBlackWhichIsCurrently99"',
)
self.assertEqual(c1_2._stack[2].lineno, 28)
c1_3 = c1_2.catch(lambda _: 3)
self.assertEqual(len(c1_3._stack), 4)
self.assertEqual(c1_3._stack[0], p._stack[0])
self.assertEqual(c1_3._stack[1], c1_1._stack[1])
self.assertEqual(c1_3._stack[2], c1_2._stack[2])
self.assertEqual(c1_3._stack[3].line, "c1_3 = c1_2.catch(lambda _: 3)")
self.assertEqual(c1_3._stack[3].lineno, 45)
c2_1 = p.then(lambda _: 10)
self.assertEqual(len(c2_1._stack), 2)
self.assertEqual(c2_1._stack[0], p._stack[0])
self.assertEqual(c2_1._stack[1].line, "c2_1 = p.then(lambda _: 10)")
self.assertEqual(c2_1._stack[1].lineno, 54)
c2_2 = c2_1.lastly(lambda: 20)
self.assertEqual(len(c2_2._stack), 3)
self.assertEqual(c2_2._stack[0], p._stack[0])
self.assertEqual(c2_2._stack[1], c2_1._stack[1])
self.assertEqual(c2_2._stack[2].line, "c2_2 = c2_1.lastly(lambda: 20)")
self.assertEqual(c2_2._stack[2].lineno, 61)
c2_3 = c2_2.then(lambda _: 30)
self.assertEqual(len(c2_3._stack), 4)
self.assertEqual(c2_3._stack[0], p._stack[0])
self.assertEqual(c2_3._stack[1], c2_1._stack[1])
self.assertEqual(c2_3._stack[2], c2_2._stack[2])
self.assertEqual(c2_3._stack[3].line, "c2_3 = c2_2.then(lambda _: 30)")
self.assertEqual(c2_3._stack[3].lineno, 69)
p.resolve(None)
self.assertEqual(
await c1_3,
"LongTextToPurposelyLargerThenTheCharacterLimitOfBlackWhichIsCurrently99"
)
self.assertEqual(await c2_3, 30)