def test_put_get():
"""
Channel is a FIFO queue. Write with put() or put_many(), then read with
get().
"""
chnl = Channel()
chnl.put(1)
chnl.put(2)
assert chnl.get() == 1
chnl.put(3)
assert chnl.get() == 2
assert chnl.get() == 3
chnl.put_many([4, 5])
assert chnl.get() == 4
assert chnl.get() == 5
def test_end_states():
"""
Once cancelled, a Channel stays that way. If ended, though,
it can be cancelled to prevent any remaining data being read.
"""
chnl = Channel()
chnl.cancel()
with pytest.raises(channel.Cancelled):
chnl.put(1)
with pytest.raises(channel.Cancelled):
chnl.get()
chnl.cancel()
with pytest.raises(channel.Cancelled):
chnl.get()
chnl.end()
with pytest.raises(channel.Cancelled):
chnl.get()
chnl = Channel()
chnl.end()
with pytest.raises(channel.Finished):
chnl.get()
with pytest.raises(channel.Finished):
chnl.put(1)
chnl.end()
with pytest.raises(channel.Finished):
chnl.get()
chnl.cancel()
with pytest.raises(channel.Cancelled):
chnl.get()
chnl = Channel()
chnl.put_many([1, 2, 3])
chnl.end()
assert chnl.get() == 1
chnl.cancel()
with pytest.raises(channel.Cancelled):
chnl.get()
def test_priority_callable():
"""
Prioritised channel can have custom sort order.
"""
chnl = Channel(priority=lambda value: -value)
values = (3, 2, 1, 1, 2, 3, 7)
chnl.put_many(values).end()
assert tuple(chnl) == tuple(sorted(values, reverse=True))
# And this still works with the gets mixed into the puts
chnl = Channel(priority=lambda value: -value)
chnl.put(2)
chnl.put(1)
assert chnl.get() == 2
chnl.put(0)
assert chnl.get() == 1
chnl.put(3)
assert chnl.get() == 3
assert chnl.get() == 0
def test_priority():
"""
FIFO behaviour can be changed to a priority queue.
"""
chnl = Channel(priority=True)
values = (3, 2, 1, 1, 2, 3, 7)
chnl.put_many(values).end()
assert tuple(chnl) == tuple(sorted(values))
# And this still works with the gets mixed into the puts
chnl = Channel(priority=True)
chnl.put(2)
chnl.put(1)
assert chnl.get() == 1
chnl.put(0)
assert chnl.get() == 0
chnl.put(3)
assert chnl.get() == 2
assert chnl.get() == 3