atlas-iac/testing/tests/test_hermes_handoff_mutation_gate.py

"""Tests for the deterministic Hermes handoff mutation gate."""

from __future__ import annotations

from pathlib import Path

from testing.quality_handoff_mutation import (
    MUTATIONS,
    Mutation,
    MutationReport,
    main,
    run_gate,
)


ROOT = Path(__file__).parents[2]


def test_every_security_mutant_is_killed() -> None:
    report = run_gate(ROOT)
    assert report.issues == ()
    assert report.score == 100.0
    assert report.killed == report.total >= 9


def test_invalid_anchor_baseline_syntax_and_survivor_are_reported() -> None:
    path = "hermes_handoff_model.py"
    cases = (
        Mutation("missing", path, "not present", "x", "pass"),
        Mutation(
            "baseline",
            path,
            "SCHEMA_VERSION = 1",
            "SCHEMA_VERSION = 2",
            "raise SystemExit(1)",
        ),
        Mutation("syntax", path, "SCHEMA_VERSION = 1", "if", "pass"),
        Mutation("survivor", path, "SCHEMA_VERSION = 1", "SCHEMA_VERSION = 2", "pass"),
    )
    report = run_gate(ROOT, cases)
    assert report.killed == 0
    assert len(report.issues) == 4
    assert report.score == 0.0


def test_main_reports_a_perfect_score(capsys) -> None:
    """Every mutant must die, and the count must track the declared set."""
    assert main() == 0
    total = len(MUTATIONS)
    assert total >= 13
    assert f"{total}/{total} (100.00%)" in capsys.readouterr().out


def test_main_reports_mutation_issues(monkeypatch, capsys) -> None:
    monkeypatch.setattr(
        "testing.quality_handoff_mutation.run_gate",
        lambda _root: MutationReport(1, 0, ("survivor",)),
    )
    assert main() == 1
    assert "survivor" in capsys.readouterr().out