thermograph/tests/test_climate.py
Emi Griffith c3bacdce0c Migrate backend dataframe layer from pandas to polars (#90)
* Migrate backend dataframe layer from pandas to polars

Replace pandas with polars across the backend, dropping both pandas and its
pyarrow parquet engine from the dependency set. numpy stays (the grading
percentile math is unchanged).

- climate.py: parquet IO, source→frame mappings, cache read/topup on polars.
  New _normalize_read casts the cached `date` column to pl.Date (older files
  were written by pandas as datetime64[ns]); frames now unify missing values as
  null so the grading boundary drops them consistently across sources.
- grading.py: keep the numpy percentile core; swap the frame→numpy bridge to
  .to_numpy()/.drop_nulls(), day-of-year/year to polars dt expressions, and the
  per-row loop to iter_rows(named=True).
- views.py: filter/anti-join/concat replace boolean-mask, isin and pd.concat;
  scalar dates are stdlib datetime.date; a local _months_before helper replaces
  DateOffset(months=) for the calendar-range default.
- app.py, migrate.py: request-date parsing uses datetime.date, removing pandas
  from the endpoint and migrate layers entirely.
- The date column is pl.Date end to end, eliminating the pandas normalize() calls
  and comparing cleanly against stdlib dates.

Payloads are unchanged: calendar, day, grade and forecast responses are
byte-for-byte identical to the pandas implementation on the same cached record.

Tests ported to polars fixtures, with added coverage for the combined feels-like
fallback, calendar month-offset (month-end/leap), and the concat/dedup
"fresher source wins" rule.

* Port notify.py to polars after merging dev's account system

Merge origin/dev (accounts + notification subscriptions) and carry the pandas→
polars migration into the newly added notify.py, which the merge brought in still
using pandas — with pandas removed from requirements this broke its import.

- notify.py: _candidate_rows filters/sorts the recent bundle with polars
  expressions and returns iter_rows dicts; date scalars are datetime.date;
  history/recent emptiness via is_empty().
- test_notify.py: synthetic history/rows built with polars + datetime.
2026-07-15 19:07:38 +00:00

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Python

"""The source→frame mappings and cache-write path (pure parts of climate.py —
no network)."""
import datetime
import polars as pl
import climate
def _om_daily(n=3):
"""A minimal Open-Meteo daily response."""
return {
"time": [f"2026-06-{d:02d}" for d in range(1, n + 1)],
"temperature_2m_max": [80.0, 90.0, None],
"temperature_2m_min": [60.0, 70.0, 55.0],
"precipitation_sum": [0.0, 0.25, 0.1],
"wind_speed_10m_max": [10.0, 20.0, 5.0],
"wind_gusts_10m_max": [15.0, 30.0, 8.0],
"apparent_temperature_max": [82.0, 95.0, 70.0],
"apparent_temperature_min": [58.0, 68.0, 50.0],
"relative_humidity_2m_mean": [50.0, 60.0, 70.0],
}
def test_to_frame_schema_and_day_filter():
df = climate._to_frame(_om_daily())
# The None tmax day is dropped: a usable climate day needs a real high/low.
assert len(df) == 2
assert df["doy"].dtype == pl.Int16
assert set(df.columns) == {"date", "tmax", "tmin", "precip", "wind", "gust",
"humid", "fmax", "fmin", "feels", "doy"}
def test_to_frame_tolerates_missing_series():
daily = _om_daily()
del daily["wind_gusts_10m_max"], daily["relative_humidity_2m_mean"]
df = climate._to_frame(daily)
assert df["gust"].is_null().all() and df["humid"].is_null().all()
assert df["tmax"].is_not_null().all() # required series unaffected
def test_combined_feels_picks_the_extreme_side():
df = climate._to_frame(_om_daily())
# Day 2: fmax 95 is 30 past the 65°F comfort point vs fmin 68 only 3 below —
# the hot side wins; both days here are hot-side days.
assert df.filter(pl.col("date") == datetime.date(2026, 6, 2))["feels"].item() == 95.0
def test_combined_feels_falls_back_to_the_present_side():
"""When one apparent-temperature side is missing, `feels` uses whichever side
is present (the null-vs-value coalesce must reproduce the old NaN fallback)."""
daily = _om_daily()
daily["apparent_temperature_max"] = [None, None, None] # hot side absent
df = climate._to_frame(daily)
row = df.filter(pl.col("date") == datetime.date(2026, 6, 1)).row(0, named=True)
assert row["feels"] == 58.0 # falls back to apparent low
def test_nasa_to_frame_converts_units_and_fills():
param = {
"T2M_MAX": {"20260601": 30.0, "20260602": -999.0}, # °C; -999 = missing
"T2M_MIN": {"20260601": 20.0, "20260602": 15.0},
"PRECTOTCORR": {"20260601": 25.4, "20260602": 0.0}, # mm
"WS10M_MAX": {"20260601": 10.0, "20260602": 5.0}, # m/s
"RH2M": {"20260601": 50.0, "20260602": 60.0},
}
df = climate._nasa_to_frame(param)
assert len(df) == 1 # the missing-tmax day dropped
row = df.row(0, named=True)
assert row["tmax"] == 86.0 # 30°C
assert row["precip"] == 1.0 # 25.4mm = 1in
assert round(row["wind"], 1) == 22.4 # 10 m/s in mph
assert row["gust"] is None # POWER has no gusts (missing -> null)
assert row["fmax"] > row["tmax"] # ≥80°F: the NWS heat index applies
def test_om_daily_params_carries_the_window():
cell = {"center_lat": 47.6, "center_lon": -122.3}
p = climate._om_daily_params(cell, start_date="2026-01-01", end_date="2026-02-01")
assert p["latitude"] == 47.6 and p["daily"] == climate.DAILY_VARS
assert p["temperature_unit"] == "fahrenheit"
assert p["start_date"] == "2026-01-01" and p["end_date"] == "2026-02-01"
p2 = climate._om_daily_params(cell, past_days=25, forecast_days=8)
assert p2["past_days"] == 25 and "start_date" not in p2
def test_write_cache_strips_the_derived_doy(tmp_path):
df = climate._to_frame(_om_daily())
path = str(tmp_path / "cell.parquet")
climate._write_cache(df, path)
stored = pl.read_parquet(path)
assert "doy" not in stored.columns
assert len(stored) == len(df)