def test_unique_list():
source = Stream()
L = source.unique(history=1).sink_to_list()
source.emit(["a"])
source.emit(["a"])
source.emit(["b"])
assert L == [["a"], ["b"]]
def test_unique_dict():
source = Stream()
L = source.unique(history=1).sink_to_list()
source.emit({"a": 1})
source.emit({"a": 1})
source.emit({"b": 1})
assert L == [{"a": 1}, {"b": 1}]