def test_no_output():
source = Stream()
assert source.emit(1) is None
def test_map_errors_raises():
a = Stream()
b = a.map(lambda x: 1 / x) # noqa: F841
with pytest.raises(ZeroDivisionError):
a.emit(0)
def test_share_common_ioloop(clean): # noqa: F811
a = Stream()
b = Stream()
aa = a.timed_window(0.01)
bb = b.timed_window(0.01)
assert aa.loop is bb.loop
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_docstrings():
for s in [Stream, Stream()]:
assert 'every element' in s.map.__doc__
assert s.map.__name__ == 'map'
assert 'predicate' in s.filter.__doc__
assert s.filter.__name__ == 'filter'
def test_zip_latest_reverse():
a = Stream()
b = Stream()
c = a.zip_latest(b)
L = c.sink_to_list()
b.emit('a')
a.emit(1)
a.emit(2)
a.emit(3)
b.emit('b')
a.emit(4)
assert L == [(1, 'a'), (2, 'a'), (3, 'a'), (4, 'b')]
def test_zip_latest_ref_counts():
a = Stream()
b = Stream()
_ = a.zip_latest(b)
ref1 = RefCounter()
a.emit(1, metadata=[{'ref': ref1}])
assert ref1.count == 1 # Retained until stream b has a value
# The lossless stream is never retained if all upstreams have a value
ref2 = RefCounter()
b.emit(2, metadata=[{'ref': ref2}])
assert ref1.count == 0
assert ref2.count == 1
# Kick out the stream b value and verify it has zero references
ref3 = RefCounter()
b.emit(3, metadata=[{'ref': ref3}])
assert ref2.count == 0
assert ref3.count == 1
# Verify the lossless value is not retained, but the lossy value is
ref4 = RefCounter()
a.emit(3, metadata=[{'ref': ref4}])
assert ref3.count == 1
assert ref4.count == 0
def test_combine_latest_ref_counts():
a = Stream()
b = Stream()
_ = a.combine_latest(b)
ref1 = RefCounter()
a.emit(1, metadata=[{'ref': ref1}])
assert ref1.count == 1
# The new value kicks out the old value
ref2 = RefCounter()
a.emit(2, metadata=[{'ref': ref2}])
assert ref1.count == 0
assert ref2.count == 1
# The value on stream a is still retained and the value on stream b is new
ref3 = RefCounter()
b.emit(3, metadata=[{'ref': ref3}])
assert ref2.count == 1
assert ref3.count == 1
def test_combine_latest_metadata():
a = Stream()
b = Stream()
L = metadata(a.combine_latest(b)).sink_to_list()
a.emit(1, metadata=[{'v': 1}])
b.emit(2, metadata=[{'v': 2}])
b.emit(3)
b.emit(4, metadata=[{'v': 4}])
assert L == [
[{
'v': 1
}, {
'v': 2
}], # first emit when 2 is introduced
[{
'v': 1
}], # 3 has no metadata but it replaces the value on 'b'
[{
'v': 1
}, {
'v': 4
}] # 4 replaces the value without metadata on 'b'
]
def test_zip_literals():
a = Stream()
b = Stream()
c = sz.zip(a, 123, b)
L = c.sink_to_list()
a.emit(1)
b.emit(2)
assert L == [(1, 123, 2)]
a.emit(4)
b.emit(5)
assert L == [(1, 123, 2), (4, 123, 5)]
def test_combine_latest_emit_on_stream():
a = Stream()
b = Stream()
c = a.combine_latest(b, emit_on=0)
L = c.sink_to_list()
a.emit(1)
b.emit('a')
a.emit(2)
a.emit(3)
b.emit('b')
a.emit(4)
assert L == [(2, 'a'), (3, 'a'), (4, 'b')]
def test_zip():
a = Stream()
b = Stream()
c = sz.zip(a, b)
L = c.sink_to_list()
a.emit(1)
b.emit('a')
a.emit(2)
b.emit('b')
assert L == [(1, 'a'), (2, 'b')]
d = Stream()
# test zip from the object itself
# zip 3 streams together
e = a.zip(b, d)
L2 = e.sink_to_list()
a.emit(1)
b.emit(2)
d.emit(3)
assert L2 == [(1, 2, 3)]
def test_timed_window_timedelta(clean): # noqa: F811
pytest.importorskip('pandas')
source = Stream(asynchronous=True)
a = source.timed_window('10ms')
assert a.interval == 0.010
def test_mixed_async():
s1 = Stream(asynchronous=False)
with pytest.raises(ValueError):
Stream(asynchronous=True, upstream=s1)
def test_stream_name_str():
source = Stream(stream_name='this is not a stream')
assert str(source) == '<this is not a stream; Stream>'
def test_zip_ref_counts():
a = Stream()
b = Stream()
_ = a.zip(b)
# The first value in a becomes buffered
ref1 = RefCounter()
a.emit(1, metadata=[{'ref': ref1}])
assert ref1.count == 1
# The second value in a also becomes buffered
ref2 = RefCounter()
a.emit(2, metadata=[{'ref': ref2}])
assert ref1.count == 1
assert ref2.count == 1
# All emitted values are removed from the buffer
ref3 = RefCounter()
b.emit(3, metadata=[{'ref': ref3}])
assert ref1.count == 0
assert ref2.count == 1 # still in the buffer
assert ref3.count == 0
def test_zip_latest():
a = Stream()
b = Stream()
c = a.zip_latest(b)
d = a.combine_latest(b, emit_on=a)
L = c.sink_to_list()
L2 = d.sink_to_list()
a.emit(1)
a.emit(2)
b.emit('a')
b.emit('b')
a.emit(3)
assert L == [(1, 'a'), (2, 'a'), (3, 'b')]
assert L2 == [(3, 'b')]
def test_unique_history():
source = Stream()
s = source.unique(maxsize=2)
s2 = source.unique(maxsize=2, hashable=False)
L = s.sink_to_list()
L2 = s2.sink_to_list()
source.emit(1)
source.emit(2)
source.emit(1)
source.emit(2)
source.emit(1)
source.emit(2)
assert L == [1, 2]
assert L == L2
source.emit(3)
source.emit(2)
assert L == [1, 2, 3]
assert L == L2
source.emit(1)
assert L == [1, 2, 3, 1]
assert L == L2
# update 2 position
source.emit(2)
# knock out 1
source.emit(3)
# update 2 position
source.emit(2)
assert L == [1, 2, 3, 1, 3]
assert L == L2
def test_triple_zip_latest():
from streamz.core import Stream
s1 = Stream()
s2 = Stream()
s3 = Stream()
s_simple = s1.zip_latest(s2, s3)
L_simple = s_simple.sink_to_list()
s1.emit(1)
s2.emit('I')
s2.emit("II")
s1.emit(2)
s2.emit("III")
s3.emit('a')
s3.emit('b')
s1.emit(3)
assert L_simple == [(1, 'III', 'a'), (2, 'III', 'a'), (3, 'III', 'b')]
def test_unique_history_dict():
source = Stream()
s = source.unique(maxsize=2, hashable=False)
L = s.sink_to_list()
a = {'hi': 'world'}
b = {'hi': 'bar'}
c = {'foo': 'bar'}
source.emit(a)
source.emit(b)
source.emit(a)
source.emit(b)
source.emit(a)
source.emit(b)
assert L == [a, b]
source.emit(c)
source.emit(b)
assert L == [a, b, c]
source.emit(a)
assert L == [a, b, c, a]
def test_zip_latest_metadata():
a = Stream()
b = Stream()
L = metadata(a.zip_latest(b)).sink_to_list()
a.emit(1, metadata=[{'v': 1}])
b.emit(2, metadata=[{'v': 2}])
a.emit(3)
b.emit(4, metadata=[{'v': 4}])
assert L == [
[{
'v': 1
}, {
'v': 2
}], # the first emit when 2 is introduced
[{
'v': 2
}] # 3 has no metadata
]
def test_union():
a = Stream()
b = Stream()
c = Stream()
L = a.union(b, c).sink_to_list()
a.emit(1)
assert L == [1]
b.emit(2)
assert L == [1, 2]
a.emit(3)
assert L == [1, 2, 3]
c.emit(4)
assert L == [1, 2, 3, 4]
def test_map_args():
source = Stream()
L = source.map(operator.add, 10).sink_to_list()
source.emit(1)
assert L == [11]
def test_collect():
source1 = Stream()
source2 = Stream()
collector = source1.collect()
L = collector.sink_to_list()
source2.sink(collector.flush)
source1.emit(1)
source1.emit(2)
assert L == []
source2.emit('anything') # flushes collector
assert L == [(1, 2)]
source2.emit('anything')
assert L == [(1, 2), ()]
source1.emit(3)
assert L == [(1, 2), ()]
source2.emit('anything')
assert L == [(1, 2), (), (3, )]
def test_percolate_loop_information(clean): # noqa: F811
source = Stream()
assert not source.loop
s = source.timed_window(0.5)
assert source.loop is s.loop
def test_timed_window_str(clean): # noqa: F811
source = Stream()
s = source.timed_window(.05)
assert str(s) == '<timed_window: 0.05>'
def test_accumulate_errors_raises():
a = Stream()
b = a.accumulate(lambda x, y: x / y, with_state=True) # noqa: F841
with pytest.raises(ZeroDivisionError):
a.emit(1)
a.emit(0)
def test_partition_str():
source = Stream()
s = source.partition(2)
assert str(s) == '<partition: 2>'
def test_slice_err():
a = Stream()
with pytest.raises(ValueError):
a.slice(end=-1)
def test_timed_window_unique():
tests = [
(0.05, sz.identity, "first", [1, 2, 1, 3, 1, 3, 3, 2], [(1, 2, 3)]),
(0.05, sz.identity, "last", [1, 2, 1, 3, 1, 3, 3, 2], [(1, 3, 2)]),
(
0.05,
len,
"last",
["f", "fo", "f", "foo", "f", "foo", "foo", "fo"],
[("f", "foo", "fo")],
),
(
0.05,
"id",
"first",
[{
"id": 0,
"foo": "bar"
}, {
"id": 1,
"foo": "bat"
}, {
"id": 0,
"foo": "baz"
}],
[({
"id": 0,
"foo": "bar"
}, {
"id": 1,
"foo": "bat"
})],
),
(
0.05,
"id",
"last",
[{
"id": 0,
"foo": "bar"
}, {
"id": 1,
"foo": "bat"
}, {
"id": 0,
"foo": "baz"
}],
[({
"id": 1,
"foo": "bat"
}, {
"id": 0,
"foo": "baz"
})],
),
]
for interval, key, keep, elements, exp_result in tests:
source = Stream(asynchronous=True)
a = source.timed_window_unique(interval, key, keep)
assert a.loop is IOLoop.current()
L = a.sink_to_list()
for ele in elements:
yield source.emit(ele)
yield gen.sleep(a.interval)
assert L
assert all(wi in elements for window in L for wi in window)
assert sum(1 for window in L for _ in window) <= len(elements)
assert L == exp_result
yield gen.sleep(a.interval)
assert not L[-1]