def test_mean():
sdf = StreamingDataFrame(columns=['x', 'y'])
mean = sdf.mean()
assert isinstance(mean, StreamingSeries)
df_out = mean.stream.sink_to_list()
x = sdf.x
x_out = x.mean().stream.sink_to_list()
df = pd.DataFrame({'x': [1, 2, 3], 'y': [4, 5, 6]})
sdf.emit(df)
sdf.emit(df)
assert assert_eq(df_out[0], df.mean())
assert assert_eq(df_out[1], df.mean())
assert x_out[0] == df.x.mean()
assert x_out[1] == df.x.mean()
def test_setitem():
df = pd.DataFrame({'x': list(range(10)), 'y': [1] * 10})
sdf = StreamingDataFrame(example=df.iloc[:0])
stream = sdf.stream
sdf['z'] = sdf['x'] * 2
sdf['a'] = 10
sdf[['c', 'd']] = sdf[['x', 'y']]
L = sdf.mean().stream.sink_to_list()
stream.emit(df.iloc[:3])
stream.emit(df.iloc[3:7])
stream.emit(df.iloc[7:])
df['z'] = df['x'] * 2
df['a'] = 10
df[['c', 'd']] = df[['x', 'y']]
assert_eq(L[-1], df.mean())