def test_offer_none():
"""
GIVEN
A channel.
WHEN
Offered None.
EXPECT
Raises ValueError.
"""
q = asyncio.Queue()
ch = Channel(q)
with pytest.raises(ValueError, match='None is not allowed on channel'):
ch.offer(None)
async def test_capacity_timeout_unblock():
"""
GIVEN
Channel is open and full.
WHEN
Wait for capacity, and timeout elapses.
EXPECT
Unblocks and returns True.
"""
q = asyncio.Queue(1)
ch = Channel(q)
ch.offer('x')
assert not await ch.capacity(timeout=0.1)
assert ch.full()
async def test_capacity():
"""
GIVEN
Channel is open and full.
WHEN
Wait for capacity.
EXPECT
Blocks.
"""
q = asyncio.Queue(1)
ch = Channel(q)
x = 'x'
ch.offer(x)
with pytest.raises(asyncio.TimeoutError):
await asyncio.wait_for(ch.capacity(), timeout=0.05)
async def test_capacity_next_reblocks():
"""
GIVEN
Channel is open and full, and two coroutines are awaiting
capacity.
WHEN
Capacity becomes available, and first unblocked coroutine
puts an item.
EXPECT
Second coroutine remains blocked.
"""
q = asyncio.Queue(1)
ch = Channel(q)
assert ch.offer('a')
b = 'b'
async def put_item():
await ch.capacity()
ch.offer(b)
asyncio.get_running_loop().call_later(0.05, ch.poll)
with pytest.raises(asyncio.TimeoutError):
await asyncio.wait_for(asyncio.gather(put_item(), ch.capacity()),
timeout=0.1)
# Verify that new item was put and unblock the second coroutine.
assert await ch.take() == b
async def test_capacity_unblock():
"""
GIVEN
Channel is open and full.
WHEN
Wait for capacity, and an item is take while blocked.
EXPECT
Unblocks and returns True.
"""
q = asyncio.Queue(1)
ch = Channel(q)
x = 'x'
ch.offer(x)
asyncio.get_running_loop().call_later(0.05, ch.poll)
assert await ch.capacity(timeout=0.1)
assert ch.offer(x)
async def test_capacity_close_unblock():
"""
GIVEN
Channel is open and full.
WHEN
Wait for capacity, and close channel.
EXPECT
Unblocks and returns False.
"""
q = asyncio.Queue(1)
ch = Channel(q)
ch.close()
assert not await ch.capacity(timeout=0.05)
assert not ch.offer('x')
def test_offer_closed():
"""
GIVEN
Channel is closed.
WHEN
Offered an item.
EXPECT
The item is not added to the queue and offer returns False.
"""
q = asyncio.Queue()
ch = Channel(q)
ch.close()
x = 'x'
assert not ch.offer(x)
assert q.empty()
def test_offer():
"""
GIVEN
Channel is not full.
WHEN
Offered an item.
EXPECT
The item is added to the queue and offer returns True.
"""
q = asyncio.Queue()
ch = Channel(q)
x = 'x'
assert ch.offer(x)
assert q.qsize() == 1
assert q.get_nowait() == x
async def test_capacity_unblock_next():
"""
GIVEN
Channel is open and full, and two coroutines are awaiting
capacity.
WHEN
Capacity becomes available, and first unblocked coroutine does
not put item.
EXPECT
Second coroutine unblocks.
"""
q = asyncio.Queue(1)
ch = Channel(q)
assert ch.offer('a')
asyncio.get_running_loop().call_later(0.05, ch.poll)
await asyncio.wait_for(asyncio.gather(ch.capacity(), ch.capacity()),
timeout=0.1)
def test_offer_full():
"""
GIVEN
Channel is full.
WHEN
Offered an item.
EXPECT
The item is not added to the queue and offer returns False.
"""
a = 'a'
q = asyncio.Queue(1)
q.put_nowait(a)
ch = Channel(q)
b = 'b'
assert not ch.offer(b)
x = q.get_nowait()
assert x != b