Move decomposition module into methods sub-package

- move the module
- unify the corresponding tests in `tests.forecasts.methods` sub-package
- make all `predict()` and the `stl()` function round results
- streamline documentation
This commit is contained in:
Alexander Hess 2021-01-31 18:50:24 +01:00
commit 08b748c867
Signed by: alexander
GPG key ID: 344EA5AB10D868E0
9 changed files with 21 additions and 14 deletions

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"""Tests for the `urban_meal_delivery.forecasts.methods` sub-package."""

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"""Test the `stl()` function."""
import math
import pandas as pd
import pytest
from tests.forecasts.conftest import NS
from tests.forecasts.conftest import VERTICAL_FREQUENCY
from urban_meal_delivery.forecasts.methods import decomposition
class TestInvalidArguments:
"""Test `stl()` with invalid arguments."""
def test_no_nans_in_time_series(self, vertical_datetime_index):
"""`stl()` requires a `time_series` without `NaN` values."""
time_series = pd.Series(dtype=float, index=vertical_datetime_index)
with pytest.raises(ValueError, match='`NaN` values'):
decomposition.stl(time_series, frequency=VERTICAL_FREQUENCY, ns=99)
def test_ns_not_odd(self, vertical_no_demand):
"""`ns` must be odd and `>= 7`."""
with pytest.raises(ValueError, match='`ns`'):
decomposition.stl(vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=8)
@pytest.mark.parametrize('ns', [-99, -1, 1, 5])
def test_ns_smaller_than_seven(self, vertical_no_demand, ns):
"""`ns` must be odd and `>= 7`."""
with pytest.raises(ValueError, match='`ns`'):
decomposition.stl(vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=ns)
def test_nt_not_odd(self, vertical_no_demand):
"""`nt` must be odd and `>= default_nt`."""
nt = 200
default_nt = math.ceil((1.5 * VERTICAL_FREQUENCY) / (1 - (1.5 / NS)))
assert nt > default_nt # sanity check
with pytest.raises(ValueError, match='`nt`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, nt=nt,
)
@pytest.mark.parametrize('nt', [-99, -1, 0, 1, 99, 159])
def test_nt_not_at_least_the_default(self, vertical_no_demand, nt):
"""`nt` must be odd and `>= default_nt`."""
# `default_nt` becomes 161.
default_nt = math.ceil((1.5 * VERTICAL_FREQUENCY) / (1 - (1.5 / NS)))
assert nt < default_nt # sanity check
with pytest.raises(ValueError, match='`nt`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, nt=nt,
)
def test_nl_not_odd(self, vertical_no_demand):
"""`nl` must be odd and `>= frequency`."""
nl = 200
assert nl > VERTICAL_FREQUENCY # sanity check
with pytest.raises(ValueError, match='`nl`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, nl=nl,
)
def test_nl_at_least_the_frequency(self, vertical_no_demand):
"""`nl` must be odd and `>= frequency`."""
nl = 77
assert nl < VERTICAL_FREQUENCY # sanity check
with pytest.raises(ValueError, match='`nl`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, nl=nl,
)
def test_ds_not_zero_or_one(self, vertical_no_demand):
"""`ds` must be `0` or `1`."""
with pytest.raises(ValueError, match='`ds`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, ds=2,
)
def test_dt_not_zero_or_one(self, vertical_no_demand):
"""`dt` must be `0` or `1`."""
with pytest.raises(ValueError, match='`dt`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, dt=2,
)
def test_dl_not_zero_or_one(self, vertical_no_demand):
"""`dl` must be `0` or `1`."""
with pytest.raises(ValueError, match='`dl`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, dl=2,
)
@pytest.mark.parametrize('js', [-1, 0])
def test_js_not_positive(self, vertical_no_demand, js):
"""`js` must be positive."""
with pytest.raises(ValueError, match='`js`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, js=js,
)
@pytest.mark.parametrize('jt', [-1, 0])
def test_jt_not_positive(self, vertical_no_demand, jt):
"""`jt` must be positive."""
with pytest.raises(ValueError, match='`jt`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, jt=jt,
)
@pytest.mark.parametrize('jl', [-1, 0])
def test_jl_not_positive(self, vertical_no_demand, jl):
"""`jl` must be positive."""
with pytest.raises(ValueError, match='`jl`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, jl=jl,
)
@pytest.mark.parametrize('ni', [-1, 0])
def test_ni_not_positive(self, vertical_no_demand, ni):
"""`ni` must be positive."""
with pytest.raises(ValueError, match='`ni`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, ni=ni,
)
def test_no_not_non_negative(self, vertical_no_demand):
"""`no` must be non-negative."""
with pytest.raises(ValueError, match='`no`'):
decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS, no=-1,
)
@pytest.mark.r
class TestValidArguments:
"""Test `stl()` with valid arguments."""
def test_structure_of_returned_dataframe(self, vertical_no_demand):
"""`stl()` returns a `pd.DataFrame` with three columns."""
result = decomposition.stl(
vertical_no_demand, frequency=VERTICAL_FREQUENCY, ns=NS,
)
assert isinstance(result, pd.DataFrame)
assert list(result.columns) == ['seasonal', 'trend', 'residual']
# Run the `stl()` function with all possible combinations of arguments,
# including default ones and explicitly set non-default ones.
@pytest.mark.parametrize('nt', [None, 163])
@pytest.mark.parametrize('nl', [None, 777])
@pytest.mark.parametrize('ds', [0, 1])
@pytest.mark.parametrize('dt', [0, 1])
@pytest.mark.parametrize('dl', [0, 1])
@pytest.mark.parametrize('js', [None, 1])
@pytest.mark.parametrize('jt', [None, 1])
@pytest.mark.parametrize('jl', [None, 1])
@pytest.mark.parametrize('ni', [2, 3])
@pytest.mark.parametrize('no', [0, 1])
def test_decompose_time_series_with_no_demand( # noqa:WPS211,WPS216
self, vertical_no_demand, nt, nl, ds, dt, dl, js, jt, jl, ni, no, # noqa:WPS110
):
"""Decomposing a time series with no demand ...
... returns a `pd.DataFrame` with three columns holding only `0.0` values.
"""
decomposed = decomposition.stl(
vertical_no_demand,
frequency=VERTICAL_FREQUENCY,
ns=NS,
nt=nt,
nl=nl,
ds=ds,
dt=dt,
dl=dl,
js=js,
jt=jt,
jl=jl,
ni=ni,
no=no, # noqa:WPS110
)
result = decomposed.sum().sum()
assert result == 0

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"""Test the `arima.predict()` and `ets.predict()` functions.
We consider both "classical" time series prediction models.
"""
import datetime as dt
import pandas as pd
import pytest
from tests import config as test_config
from tests.forecasts.conftest import VERTICAL_FREQUENCY
from urban_meal_delivery import config
from urban_meal_delivery.forecasts.methods import arima
from urban_meal_delivery.forecasts.methods import ets
@pytest.fixture
def forecast_interval():
"""A `pd.Index` with `DateTime` values ...
... that takes place one day after the `START`-`END` horizon and
resembles an entire day (`12` "start_at" values as we use `LONG_TIME_STEP`).
"""
future_day = test_config.END.date() + dt.timedelta(days=1)
first_start_at = dt.datetime(
future_day.year, future_day.month, future_day.day, config.SERVICE_START, 0,
)
end_of_day = dt.datetime(
future_day.year, future_day.month, future_day.day, config.SERVICE_END, 0,
)
gen = (
start_at
for start_at in pd.date_range(
first_start_at, end_of_day, freq=f'{test_config.LONG_TIME_STEP}T',
)
if config.SERVICE_START <= start_at.hour < config.SERVICE_END
)
index = pd.Index(gen)
index.name = 'start_at'
return index
@pytest.fixture
def forecast_time_step():
"""A `pd.Index` with one `DateTime` value, resembling `NOON`."""
future_day = test_config.END.date() + dt.timedelta(days=1)
start_at = dt.datetime(
future_day.year, future_day.month, future_day.day, test_config.NOON, 0,
)
index = pd.Index([start_at])
index.name = 'start_at'
return index
@pytest.mark.r
@pytest.mark.parametrize('func', [arima.predict, ets.predict])
class TestMakePredictions:
"""Make predictions with `arima.predict()` and `ets.predict()`."""
def test_training_data_contains_nan_values(
self, func, vertical_no_demand, forecast_interval,
):
"""`training_ts` must not contain `NaN` values."""
vertical_no_demand.iloc[0] = pd.NA
with pytest.raises(ValueError, match='must not contain `NaN`'):
func(
training_ts=vertical_no_demand,
forecast_interval=forecast_interval,
frequency=VERTICAL_FREQUENCY,
)
def test_structure_of_returned_dataframe(
self, func, vertical_no_demand, forecast_interval,
):
"""Both `.predict()` return a `pd.DataFrame` with five columns."""
result = func(
training_ts=vertical_no_demand,
forecast_interval=forecast_interval,
frequency=VERTICAL_FREQUENCY,
)
assert isinstance(result, pd.DataFrame)
assert list(result.columns) == [
'prediction',
'low80',
'high80',
'low95',
'high95',
]
def test_predict_horizontal_time_series_with_no_demand(
self, func, horizontal_no_demand, forecast_time_step,
):
"""Predicting a horizontal time series with no demand ...
... returns a `pd.DataFrame` with five columns holding only `0.0` values.
"""
predictions = func(
training_ts=horizontal_no_demand,
forecast_interval=forecast_time_step,
frequency=7,
)
result = predictions.sum().sum()
assert result == 0
def test_predict_vertical_time_series_with_no_demand(
self, func, vertical_no_demand, forecast_interval,
):
"""Predicting a vertical time series with no demand ...
... returns a `pd.DataFrame` with five columns holding only `0.0` values.
"""
predictions = func(
training_ts=vertical_no_demand,
forecast_interval=forecast_interval,
frequency=VERTICAL_FREQUENCY,
)
result = predictions.sum().sum()
assert result == 0