thermograph/tests/data/test_meteostat.py
Emi Griffith b4d8d67825 Add Meteostat gust supplier for the gust-less backup sources
NASA POWER (history) and MET Norway (forecast) carry no wind gusts, but gust is
a graded metric. This adds data/meteostat.py, which finds the nearest Meteostat
station to a cell and reads its daily peak gust (wpgt) from the keyless gzipped
bulk endpoints, filling the gust column on the NASA POWER history frame. Where no
station is within ~100 km it estimates from sustained wind (wind * GUST_FACTOR).

Bulk files (station list + per-station daily) are cached on disk so steady-state
network IO is near zero, and any lookup/fetch failure degrades to pure estimation
so a history fetch never fails. A constant estimate factor makes an estimated
gust redundant with wind, so real signal comes only where a station backs it.

Activates once NASA POWER becomes the primary history source; Open-Meteo already
carries its own gusts. New history_gust / meteostat_stations metrics phases map
to the meteostat source.
2026-07-22 21:39:09 -07:00

96 lines
4 KiB
Python

"""Unit tests for the Meteostat gust supplier — all hermetic (no network): the
station index and per-station daily fetch are monkeypatched, and the pure parse
helpers are fed literal payloads."""
import datetime
import json
import numpy as np
import polars as pl
import pytest
from data import meteostat
def _frame(gust=(None, None, None), wind=(10.0, 20.0, None)):
return pl.DataFrame(
{
"date": [datetime.date(2020, 1, 1), datetime.date(2020, 1, 2),
datetime.date(2020, 1, 3)],
"wind": list(wind),
"gust": pl.Series(list(gust), dtype=pl.Float64),
}
)
def test_parse_daily_csv_converts_kmh_to_mph_and_skips_blanks():
csv = "\n".join([
"2020-01-01,,,,,,,,50.0,,", # wpgt (col 8) = 50 km/h
"2020-01-02,,,,,,,,,,", # no gust -> skipped
"2020-01-03,,,,,,,,80.0,,", # wpgt = 80 km/h
"bad-date,,,,,,,,50.0,,", # unparseable date -> skipped
"x,y", # too few columns -> skipped
])
out = meteostat._parse_daily_csv(csv)
assert set(out) == {datetime.date(2020, 1, 1), datetime.date(2020, 1, 3)}
assert out[datetime.date(2020, 1, 1)] == pytest.approx(50.0 * meteostat.KMH_TO_MPH)
assert out[datetime.date(2020, 1, 3)] == pytest.approx(80.0 * meteostat.KMH_TO_MPH)
def test_parse_stations_skips_entries_without_id_or_coords():
raw = json.dumps([
{"id": "A", "location": {"latitude": 47.6, "longitude": -122.3}},
{"id": "B", "location": {"latitude": 51.5, "longitude": -0.1}},
{"id": "C", "location": {}}, # no coords -> skip
{"location": {"latitude": 1, "longitude": 2}}, # no id -> skip
]).encode()
ids, lats, lons = meteostat._parse_stations(raw)
assert ids == ["A", "B"]
assert lats.tolist() == [47.6, 51.5]
assert lons.tolist() == [-122.3, -0.1]
def test_nearest_station_picks_closest_within_range(monkeypatch):
monkeypatch.setattr(meteostat, "_STATIONS",
(["seattle", "london"],
np.array([47.6, 51.5]), np.array([-122.3, -0.1])))
assert meteostat.nearest_station(47.61, -122.31) == "seattle"
# Middle of the Pacific — both stations are far beyond MAX_STATION_KM.
assert meteostat.nearest_station(0.0, -160.0) is None
def test_fill_gusts_prefers_measured_then_estimates(monkeypatch):
monkeypatch.setattr(meteostat, "nearest_station", lambda lat, lon: "s1")
monkeypatch.setattr(meteostat, "daily_gusts",
lambda sid: {datetime.date(2020, 1, 1): 33.0})
out = meteostat.fill_gusts(47.6, -122.3, _frame())
gust = out["gust"].to_list()
assert gust[0] == pytest.approx(33.0) # measured wins
assert gust[1] == pytest.approx(20.0 * meteostat.GUST_FACTOR) # estimated from wind
assert gust[2] is None # no wind -> no estimate
def test_fill_gusts_estimates_everywhere_with_no_station(monkeypatch):
monkeypatch.setattr(meteostat, "nearest_station", lambda lat, lon: None)
out = meteostat.fill_gusts(0.0, 0.0, _frame())
gust = out["gust"].to_list()
assert gust[0] == pytest.approx(10.0 * meteostat.GUST_FACTOR)
assert gust[1] == pytest.approx(20.0 * meteostat.GUST_FACTOR)
assert gust[2] is None
def test_fill_gusts_degrades_on_fetch_error(monkeypatch):
def _boom(lat, lon):
raise RuntimeError("meteostat down")
monkeypatch.setattr(meteostat, "nearest_station", _boom)
# Must not raise — falls back to pure estimation.
out = meteostat.fill_gusts(47.6, -122.3, _frame())
assert out["gust"].to_list()[1] == pytest.approx(20.0 * meteostat.GUST_FACTOR)
def test_fill_gusts_noop_when_source_has_gusts(monkeypatch):
def _fail(*a, **k):
raise AssertionError("must not consult Meteostat when gusts already present")
monkeypatch.setattr(meteostat, "nearest_station", _fail)
df = _frame(gust=(40.0, 41.0, 42.0))
out = meteostat.fill_gusts(47.6, -122.3, df)
assert out["gust"].to_list() == [40.0, 41.0, 42.0]