M54: harden operations and demo resilience

backend/tests/test_seed_generation.py

@@ -0,0 +1,73 @@
+from __future__ import annotations
+
+import csv
+import subprocess
+import sys
+from pathlib import Path
+
+REPOSITORY_ROOT = next(
+    parent
+    for parent in Path(__file__).resolve().parents
+    if (parent / "seed" / "generate_seed.py").is_file()
+)
+SEED_DIRECTORY = REPOSITORY_ROOT / "seed"
+
+
+def _rows_by_ref(path: Path) -> dict[str, dict[str, str]]:
+    with path.open(newline="", encoding="utf-8") as handle:
+        rows = list(csv.DictReader(handle))
+    assert all(None not in row for row in rows), f"malformed CSV row in {path.name}"
+    return {row["public_ref"]: row for row in rows}
+
+
+def test_generator_reproduces_committed_seed_snapshot_byte_for_byte(tmp_path: Path):
+    subprocess.run(
+        [
+            sys.executable,
+            str(SEED_DIRECTORY / "generate_seed.py"),
+            "--anchor",
+            "2026-08-01",
+            "--seed",
+            "20260801",
+            "--out",
+            str(tmp_path),
+        ],
+        cwd=REPOSITORY_ROOT,
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+
+    committed_files = sorted(SEED_DIRECTORY.glob("*.csv"))
+    generated_files = sorted(tmp_path.glob("*.csv"))
+    assert [path.name for path in generated_files] == [path.name for path in committed_files]
+    for committed in committed_files:
+        generated = tmp_path / committed.name
+        assert generated.read_bytes() == committed.read_bytes(), (
+            f"{committed.name} differs from the deterministic generated snapshot"
+        )
+
+    bookings = _rows_by_ref(tmp_path / "bookings.csv")
+    inspections = _rows_by_ref(tmp_path / "inspections.csv")
+    issues = _rows_by_ref(tmp_path / "data_quality_issues.csv")
+
+    assert int(bookings["BK-H-0007"]["end_odometer_km"]) < int(
+        bookings["BK-H-0057"]["end_odometer_km"]
+    )
+    assert int(bookings["BK-H-0010"]["end_odometer_km"]) < int(
+        bookings["BK-H-0060"]["end_odometer_km"]
+    )
+    assert inspections["INSP-0007"]["odometer_km"] == bookings["BK-H-0007"]["end_odometer_km"]
+    assert inspections["INSP-0010"]["odometer_km"] == bookings["BK-H-0010"]["end_odometer_km"]
+    assert inspections["INSP-0001"]["completed_at"] == bookings["BK-H-0001"]["ends_at"]
+
+    expected_issue_refs = {f"DQ-{index:04d}" for index in range(5, 22)}
+    assert expected_issue_refs <= issues.keys()
+    assert all(
+        issues[public_ref]["evidence"] != "Synthetic deterministic seed issue"
+        for public_ref in expected_issue_refs
+    )
+    assert "INSP-0007" in issues["DQ-0007"]["evidence"]
+    assert "INSP-0057" in issues["DQ-0007"]["evidence"]
+    assert "INSP-0010" in issues["DQ-0010"]["evidence"]
+    assert "INSP-0060" in issues["DQ-0010"]["evidence"]