def test_connect_combine_latest():
a = Stream()
b = Stream()
c = Stream()
x = a.combine_latest(b, emit_on=a)
L = x.sink_to_list()
c.connect(x)
b.emit(1)
c.emit(1)
a.emit(1)
assert L == [(1, 1, 1)]
def test_connect_zip():
a = Stream()
b = Stream()
c = Stream()
x = a.zip(b)
L = x.sink_to_list()
c.connect(x)
a.emit(1)
b.emit(1)
assert not L
c.emit(1)
assert L == [(1, 1, 1)]
def test_disconnect():
source = Stream()
upstream = Stream()
L = upstream.sink_to_list()
source.emit(1)
assert L == []
source.connect(upstream)
source.emit(2)
source.emit(3)
assert L == [2, 3]
source.disconnect(upstream)
source.emit(4)
assert L == [2, 3]
def test_connect():
source_downstream = Stream()
# connect assumes this default behaviour
# of stream initialization
assert not source_downstream.downstreams
assert source_downstream.upstreams == [None]
# initialize the second stream to connect to
source_upstream = Stream()
sout = source_downstream.map(lambda x : x + 1)
L = list()
sout = sout.map(L.append)
source_upstream.connect(source_downstream)
source_upstream.emit(2)
source_upstream.emit(4)
assert L == [3, 5]
