def test_ewm_mean():
sdf = DataFrame(example=pd.DataFrame(columns=['x', 'y']))
L = sdf.ewm(1).mean().stream.gather().sink_to_list()
sdf.emit(pd.DataFrame({'x': [1.], 'y': [2.]}))
sdf.emit(pd.DataFrame({'x': [2.], 'y': [3.]}))
sdf.emit(pd.DataFrame({'x': [3.], 'y': [4.]}))
result = pd.concat(L, ignore_index=True)
df = pd.DataFrame({'x': [1., 2., 3.], 'y': [2., 3., 4.]})
expected = df.ewm(1).mean()
assert_eq(result, expected)
def test_ewm_notimplemented(func):
sdf = DataFrame(example=pd.DataFrame(columns=['x', 'y']))
with pytest.raises(NotImplementedError):
func(sdf.ewm(1))
def test_raise_invalid_argument(arg):
sdf = DataFrame(example=pd.DataFrame(columns=['x', 'y']))
param = {arg: -1}
with pytest.raises(ValueError):
sdf.ewm(**param)
def test_ewm_raise_no_argument():
sdf = DataFrame(example=pd.DataFrame(columns=['x', 'y']))
with pytest.raises(ValueError, match="Must pass one of"):
sdf.ewm()
def test_ewm_raise_multiple_arguments():
sdf = DataFrame(example=pd.DataFrame(columns=['x', 'y']))
with pytest.raises(ValueError, match="Can only provide one of"):
sdf.ewm(com=1, halflife=1)
