feat: GIAS code->name dictionaries generated from live bulk CSV

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/tests/test_gias_codes.py

@@ -0,0 +1,83 @@
+"""Tests for the GIAS code->name dictionaries (spec 2026-07-09).
+
+The dictionaries are generated from the live GIAS bulk CSV by
+pipeline/scripts/generate_gias_codes.py — these tests assert the module's
+contract, key sentinel values the marts/UI depend on, and that the pipeline
+copy has not drifted from the canonical backend module.
+"""
+
+import math
+from pathlib import Path
+
+from backend.gias_codes import (
+    ADMISSIONS_POLICY,
+    ESTABLISHMENT_STATUS,
+    OFFICIAL_SIXTH_FORM,
+    PHASE_OF_EDUCATION,
+    RELIGIOUS_CHARACTER,
+    SCHOOL_TYPE,
+    translate,
+)
+
+REPO = Path(__file__).resolve().parents[2]
+
+
+def test_translate_known_code():
+    open_code = next(c for c, n in ESTABLISHMENT_STATUS.items() if n == "Open")
+    assert translate(open_code, ESTABLISHMENT_STATUS) == "Open"
+
+
+def test_translate_unknown_code_degrades_gracefully():
+    assert translate(9999, ESTABLISHMENT_STATUS) == "Unknown (9999)"
+
+
+def test_translate_none_and_nan_return_none():
+    assert translate(None, ESTABLISHMENT_STATUS) is None
+    assert translate(float("nan"), ESTABLISHMENT_STATUS) is None
+
+
+def test_translate_accepts_float_codes():
+    # pd.read_sql yields float columns when NULLs are present
+    open_code = next(c for c, n in ESTABLISHMENT_STATUS.items() if n == "Open")
+    assert translate(float(open_code), ESTABLISHMENT_STATUS) == "Open"
+
+
+def test_sentinel_names_present():
+    """Names the marts/UI compare against must exist verbatim."""
+    assert "Open" in ESTABLISHMENT_STATUS.values()
+    assert "Open, but proposed to close" in ESTABLISHMENT_STATUS.values()
+    assert "Has a sixth form" in OFFICIAL_SIXTH_FORM.values()
+    assert "Primary" in PHASE_OF_EDUCATION.values()
+    assert "Secondary" in PHASE_OF_EDUCATION.values()
+    assert "Does not apply" in RELIGIOUS_CHARACTER.values()
+    assert all(len(d) > 0 for d in (
+        SCHOOL_TYPE, ESTABLISHMENT_STATUS, PHASE_OF_EDUCATION,
+        OFFICIAL_SIXTH_FORM, RELIGIOUS_CHARACTER, ADMISSIONS_POLICY,
+    ))
+
+
+def test_pipeline_copy_is_identical():
+    canonical = (REPO / "backend" / "gias_codes.py").read_text()
+    copy = (REPO / "pipeline" / "scripts" / "gias_codes.py").read_text()
+    assert canonical == copy, (
+        "pipeline/scripts/gias_codes.py has drifted from backend/gias_codes.py — "
+        "regenerate with pipeline/scripts/generate_gias_codes.py and copy the file"
+    )
+
+
+def test_seed_matches_dictionaries():
+    import csv
+    fields = {
+        "school_type": SCHOOL_TYPE,
+        "establishment_status": ESTABLISHMENT_STATUS,
+        "phase_of_education": PHASE_OF_EDUCATION,
+        "official_sixth_form": OFFICIAL_SIXTH_FORM,
+        "religious_character": RELIGIOUS_CHARACTER,
+        "admissions_policy": ADMISSIONS_POLICY,
+    }
+    seed_path = REPO / "pipeline" / "transform" / "seeds" / "gias_code_names.csv"
+    seed: dict[str, dict[int, str]] = {k: {} for k in fields}
+    with open(seed_path, newline="") as fh:
+        for row in csv.DictReader(fh):
+            seed[row["field"]][int(row["code"])] = row["name"]
+    assert seed == fields