chore(release): prepare v0.3.1

tests/release/test_ruff_ratchet.py

@@ -0,0 +1,24 @@
+from scripts.ruff_ratchet import BASELINE_BY_RULE, BASELINE_TOTAL, baseline_regressions
+
+
+def _diagnostics(**counts: int) -> list[dict[str, str]]:
+    return [{"code": code} for code, count in counts.items() for _ in range(count)]
+
+
+def test_exact_baseline_passes() -> None:
+    diagnostics = _diagnostics(**BASELINE_BY_RULE)
+    assert len(diagnostics) == BASELINE_TOTAL
+    assert baseline_regressions(diagnostics) == []
+
+
+def test_new_rule_fails_from_zero_baseline() -> None:
+    assert baseline_regressions([{"code": "E501"}]) == ["E501: 1 > 0"]
+
+
+def test_existing_rule_increase_fails() -> None:
+    diagnostics = _diagnostics(I001=BASELINE_BY_RULE["I001"] + 1)
+    assert baseline_regressions(diagnostics) == ["I001: 91 > 90"]
+
+
+def test_reduced_debt_passes() -> None:
+    assert baseline_regressions(_diagnostics(I001=1, F401=1)) == []