perfect-postcode/pipeline/transform/test_crime.py
2026-05-25 13:20:17 +01:00

228 lines
8.2 KiB
Python

import polars as pl
from pipeline.transform.crime import find_street_crime_csvs, transform_crime
def test_find_street_crime_csvs_ignores_archive_sidecars(tmp_path):
crime_dir = tmp_path / "crime"
month_dir = crime_dir / "2024-01"
month_dir.mkdir(parents=True)
street = month_dir / "2024-01-test-force-street.csv"
street.touch()
(month_dir / "2024-01-test-force-outcomes.csv").touch()
(month_dir / "2024-01-test-force-stop-and-search.csv").touch()
(crime_dir / "notes.csv").touch()
csvs, ignored_count = find_street_crime_csvs(crime_dir)
assert csvs == [street]
assert ignored_count == 3
def test_transform_crime_reads_only_street_crime_csvs(tmp_path):
crime_dir = tmp_path / "crime"
month_dir = crime_dir / "2024-01"
month_dir.mkdir(parents=True)
(month_dir / "2024-01-test-force-street.csv").write_text(
"\n".join(
[
"Crime ID,Month,Reported by,Falls within,Longitude,Latitude,Location,LSOA code,LSOA name,Crime type,Last outcome category,Context",
"1,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000001,Test LSOA,Burglary,Under investigation,",
"2,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000001,Test LSOA,Burglary,Under investigation,",
"3,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,,No LSOA,Robbery,Under investigation,",
]
)
+ "\n"
)
(month_dir / "2024-01-test-force-outcomes.csv").write_text(
"Crime ID,Month,Reported by,Outcome type\n1,2024-01,Test Force,Charged\n"
)
output = tmp_path / "crime.parquet"
transform_crime(crime_dir, output)
result = pl.read_parquet(output).to_dicts()
assert result == [{"LSOA code": "E01000001", "Burglary (avg/yr)": 24.0}]
def test_transform_crime_annualises_over_all_valid_months(tmp_path):
crime_dir = tmp_path / "crime"
jan_dir = crime_dir / "2024-01"
feb_dir = crime_dir / "2024-02"
jan_dir.mkdir(parents=True)
feb_dir.mkdir(parents=True)
header = "Crime ID,Month,Reported by,Falls within,Longitude,Latitude,Location,LSOA code,LSOA name,Crime type,Last outcome category,Context"
(jan_dir / "2024-01-test-force-street.csv").write_text(
"\n".join(
[
header,
"1,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000001,Test LSOA,Burglary,Under investigation,",
"2,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000001,Test LSOA,Burglary,Under investigation,",
"3,2024-01,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000002,Other LSOA,Robbery,Under investigation,",
]
)
+ "\n"
)
(feb_dir / "2024-02-test-force-street.csv").write_text(
"\n".join(
[
header,
"4,2024-02,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000002,Other LSOA,Robbery,Under investigation,",
]
)
+ "\n"
)
output = tmp_path / "crime.parquet"
transform_crime(crime_dir, output)
result = pl.read_parquet(output).sort("LSOA code").to_dicts()
assert result == [
{
"LSOA code": "E01000001",
"Burglary (avg/yr)": 12.0,
"Robbery (avg/yr)": 0.0,
},
{
"LSOA code": "E01000002",
"Burglary (avg/yr)": 0.0,
"Robbery (avg/yr)": 12.0,
},
]
def test_transform_crime_writes_by_year_output(tmp_path):
crime_dir = tmp_path / "crime"
jan23 = crime_dir / "2023-01"
jan24 = crime_dir / "2024-01"
feb24 = crime_dir / "2024-02"
for d in (jan23, jan24, feb24):
d.mkdir(parents=True)
header = "Crime ID,Month,Reported by,Falls within,Longitude,Latitude,Location,LSOA code,LSOA name,Crime type,Last outcome category,Context"
(jan23 / "2023-01-test-force-street.csv").write_text(
"\n".join(
[
header,
"1,2023-01,F,F,-0.1,51.5,X,E01000001,L,Burglary,U,",
"2,2023-01,F,F,-0.1,51.5,X,E01000001,L,Robbery,U,",
]
)
+ "\n"
)
(jan24 / "2024-01-test-force-street.csv").write_text(
"\n".join(
[
header,
"3,2024-01,F,F,-0.1,51.5,X,E01000001,L,Burglary,U,",
"4,2024-01,F,F,-0.1,51.5,X,E01000001,L,Burglary,U,",
]
)
+ "\n"
)
(feb24 / "2024-02-test-force-street.csv").write_text(
"\n".join(
[
header,
"5,2024-02,F,F,-0.1,51.5,X,E01000001,L,Anti-social behaviour,U,",
]
)
+ "\n"
)
output = tmp_path / "crime.parquet"
by_year_output = tmp_path / "crime_by_year.parquet"
transform_crime(crime_dir, output, by_year_output)
by_year = pl.read_parquet(by_year_output)
assert by_year.height == 1
cols = set(by_year.columns)
assert "Burglary (by year)" in cols
assert "Serious crime (by year)" in cols
assert "Minor crime (by year)" in cols
row = by_year.row(0, named=True)
burglary = sorted(row["Burglary (by year)"], key=lambda r: r["year"])
# 2023: 1 burglary in 1 month → 12/yr; 2024: 2 in 2 months → 12/yr
assert burglary == [
{"year": 2023, "count": 12.0},
{"year": 2024, "count": 12.0},
]
# Serious crime in 2023 = Burglary(12) + Robbery(12) = 24
serious = {p["year"]: p["count"] for p in row["Serious crime (by year)"]}
assert serious[2023] == 24.0
assert serious[2024] == 12.0
def test_transform_crime_fails_without_valid_months(tmp_path):
crime_dir = tmp_path / "crime"
month_dir = crime_dir / "2024-01"
month_dir.mkdir(parents=True)
(month_dir / "2024-01-test-force-street.csv").write_text(
"\n".join(
[
"Crime ID,Month,Reported by,Falls within,Longitude,Latitude,Location,LSOA code,LSOA name,Crime type,Last outcome category,Context",
"1,,Test Force,Test Force,-0.1,51.5,On or near Test Street,E01000001,Test LSOA,Burglary,Under investigation,",
]
)
+ "\n"
)
output = tmp_path / "crime.parquet"
try:
transform_crime(crime_dir, output)
except ValueError as exc:
assert "No valid crime months" in str(exc)
else:
raise AssertionError("Expected ValueError")
def test_transform_crime_applies_lsoa_2011_to_2021_lookup(tmp_path):
crime_dir = tmp_path / "crime"
month_dir = crime_dir / "2024-01"
month_dir.mkdir(parents=True)
header = "Crime ID,Month,Reported by,Falls within,Longitude,Latitude,Location,LSOA code,LSOA name,Crime type,Last outcome category,Context"
# E01000001 was split into two 2021 LSOAs; E01000099 is unchanged.
(month_dir / "2024-01-test-force-street.csv").write_text(
"\n".join(
[
header,
"1,2024-01,F,F,-0.1,51.5,X,E01000001,L,Burglary,U,",
"2,2024-01,F,F,-0.1,51.5,X,E01000001,L,Burglary,U,",
"3,2024-01,F,F,-0.1,51.5,X,E01000099,L,Burglary,U,",
]
)
+ "\n"
)
lookup_path = tmp_path / "lookup.parquet"
pl.DataFrame(
{
"lsoa11": ["E01000001", "E01000001", "E01000099"],
"lsoa21": ["E01000050", "E01000051", "E01000099"],
}
).write_parquet(lookup_path)
output = tmp_path / "crime.parquet"
by_year_output = tmp_path / "by_year.parquet"
transform_crime(crime_dir, output, by_year_output, lookup_path)
# Split LSOA: 2 burglaries split evenly → 1/yr each child, annualised to 12/yr each.
avg = pl.read_parquet(output).sort("LSOA code").to_dicts()
assert avg == [
{"LSOA code": "E01000050", "Burglary (avg/yr)": 12.0},
{"LSOA code": "E01000051", "Burglary (avg/yr)": 12.0},
{"LSOA code": "E01000099", "Burglary (avg/yr)": 12.0},
]
by_year = pl.read_parquet(by_year_output).sort("LSOA code").to_dicts()
burglaries = {row["LSOA code"]: row["Burglary (by year)"] for row in by_year}
assert burglaries["E01000050"] == [{"year": 2024, "count": 12.0}]
assert burglaries["E01000051"] == [{"year": 2024, "count": 12.0}]
assert burglaries["E01000099"] == [{"year": 2024, "count": 12.0}]