test: add quality-depth gates and mature CPU coverage

tests/test_quality_gate_scripts.py

@@ -0,0 +1,70 @@
+"""Unit tests for quality-depth gate helpers."""
+
+from __future__ import annotations
+
+import json
+from types import SimpleNamespace
+
+from scripts import check_mutation_score
+from scripts import run_repeat_gate
+
+
+def test_mutation_score_accepts_exact_floor_and_rejects_regression():
+    stats = {"killed": 70, "total": 100, "check_was_interrupted_by_user": 0}
+    assert check_mutation_score.validate_mutation_stats(stats, minimum=70) == []
+    assert check_mutation_score.validate_mutation_stats(stats, minimum=70.01) == [
+        "mutation score 70.00% (70/100) is below the 70.01% floor",
+    ]
+
+
+def test_mutation_score_rejects_malformed_and_interrupted_runs():
+    assert check_mutation_score.validate_mutation_stats(
+        {"killed": True, "total": 1}, minimum=70,
+    ) == ["mutation statistics require a non-negative integer 'killed'"]
+    assert check_mutation_score.validate_mutation_stats(
+        {"killed": 1, "total": 1, "check_was_interrupted_by_user": 1}, minimum=70,
+    ) == ["mutation run was interrupted"]
+
+
+def test_repeat_orders_are_distinct_and_deterministic():
+    paths = ["a", "b", "c", "d"]
+    assert run_repeat_gate.test_orders(paths) == [
+        ["a", "b", "c", "d"],
+        ["d", "c", "b", "a"],
+        ["a", "c", "b", "d"],
+    ]
+
+
+def test_repeat_gate_records_each_pass(monkeypatch, tmp_path):
+    calls = []
+
+    def fake_run(command, **kwargs):
+        calls.append((command, kwargs["env"]["PYTHONHASHSEED"]))
+        return SimpleNamespace(returncode=0, stdout="2 passed\n", stderr="")
+
+    monkeypatch.setattr(run_repeat_gate.subprocess, "run", fake_run)
+    output = tmp_path / "repeat.json"
+    assert run_repeat_gate.run_repeat_gate(
+        ["first.py", "second.py"], output=output, python="python-fixture",
+    ) == 0
+    evidence = json.loads(output.read_text())
+    assert evidence["status"] == "passed"
+    assert [entry["python_hash_seed"] for entry in evidence["passes"]] == [
+        "0", "1", "8675309",
+    ]
+    assert calls[0][0] == [
+        "python-fixture", "-m", "pytest", "--no-cov", "-q", "first.py", "second.py",
+    ]
+
+
+def test_repeat_gate_stops_and_preserves_failure_output(monkeypatch, tmp_path):
+    def fake_run(*_args, **_kwargs):
+        return SimpleNamespace(returncode=3, stdout="failed output", stderr="failure detail")
+
+    monkeypatch.setattr(run_repeat_gate.subprocess, "run", fake_run)
+    output = tmp_path / "repeat.json"
+    assert run_repeat_gate.run_repeat_gate(["test.py"], output=output) == 3
+    evidence = json.loads(output.read_text())
+    assert evidence["status"] == "failed"
+    assert len(evidence["passes"]) == 1
+    assert evidence["passes"][0]["stderr"] == "failure detail"