async def test_item_timeout_unblock():
"""
GIVEN
Channel is open and empty.
WHEN
Wait for item, and timeout elapses.
EXPECT
Unblocks and returns False.
"""
q = asyncio.Queue()
ch = Channel(q)
assert not await ch.item(timeout=0.05)
assert ch.empty()
async def test_item_close_unblock():
"""
GIVEN
Channel is open and empty.
WHEN
Wait for item, and close channel.
EXPECT
Unblocks and returns False.
"""
q = asyncio.Queue()
ch = Channel(q)
asyncio.get_running_loop().call_later(0.05, ch.close)
assert not await ch.item(timeout=0.1)
assert ch.empty()
async def test_item_next_reblocks():
"""
GIVEN
Channel is open and empty, and two coroutines are awaiting
an item.
WHEN
An item becomes available, and first unblocked coroutine
takes it.
EXPECT
Second coroutine remains blocked.
"""
q = asyncio.Queue(1)
ch = Channel(q)
async def take_item():
await ch.item()
ch.poll()
asyncio.get_running_loop().call_later(0.05, ch.offer, 'a')
with pytest.raises(asyncio.TimeoutError):
await asyncio.wait_for(asyncio.gather(take_item(), ch.item()),
timeout=0.1)
assert ch.empty()
await ch.put('b') # Unblock the second coroutine.