test_lint_changed.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_linter/test_lint_changed.py
 
"""
Purpose
-------
Regression tests for ``oct lint --changed`` (Phase 4C — G-C4).
 
Responsibilities
----------------
- Verify the Phase 4A ``_git_changed_files`` shim still works.
- Verify that ``--changed`` lints only git-modified Python files.
- Verify graceful fallback in non-git directories.
 
Diagnostics
-----------
Domain: LINT-TESTS
Levels:
    L2 — test lifecycle
    L3 — assertion details
    L4 — deep tracing
 
Contracts
---------
- All tests use tmp_path so they are automatically cleaned up.
"""
 
import json
import shutil
import subprocess
import textwrap
from pathlib import Path
 
import pytest
 
 
# =====================================================================
# Helpers
# =====================================================================
 
 
def _git_available() -> bool:
    return shutil.which("git") is not None
 
 
def _git(repo: Path, *args: str, check: bool = True):
    return subprocess.run(
        ["git", *args],
        cwd=repo,
        check=check,
        capture_output=True,
        text=True,
    )
 
 
def _make_lint_project(tmp_path: Path) -> Path:
    """Create a git repo with pyproject.toml and one committed Python file."""
    root = tmp_path / "lintproj"
    root.mkdir()
    (root / "src").mkdir()
    (root / "tests").mkdir()
    (root / "docs").mkdir()
    (root / "oc_diagnostics").mkdir()
    (root / "pyproject.toml").write_text(
        '[project]\nname = "lintproj"\n', encoding="utf-8",
    )
 
    compliant = textwrap.dedent("""\
        #!/usr/bin/env python3
        # -*- coding: utf-8 -*-
        # src/ok.py
 
        \"\"\"
        Purpose
        -------
        A compliant module.
 
        Responsibilities
        ----------------
        - None.
 
        Diagnostics
        -----------
        Domain: TEST
        Levels:
            L1 — errors
            L2 — lifecycle
            L3 — details
            L4 — deep trace
 
        Contracts
        ---------
        - None.
        \"\"\"
 
        from oc_diagnostics import _dbg
 
        x = 1
    """)
    (root / "src" / "ok.py").write_text(compliant, encoding="utf-8")
    (root / "tests" / "test_ok.py").write_text(
        '"""Stub test."""\ndef test_ok():\n    pass\n', encoding="utf-8",
    )
 
    _git(root, "init", "--quiet", "-b", "main")
    _git(root, "config", "user.email", "test@example.com")
    _git(root, "config", "user.name", "Test")
    _git(root, "config", "commit.gpgsign", "false")
    _git(root, "add", "-A")
    _git(root, "commit", "-m", "initial", "--quiet")
    return root
 
 
# =====================================================================
# Tests
# =====================================================================
 
 
class TestLintChanged:
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_no_changes_reports_nothing(self, tmp_path):
        """--changed with a clean working tree → 'No modified Python files'."""
        root = _make_lint_project(tmp_path)
        from oct.linter.oct_lint import run_linter
        result = run_linter(root, ["--changed"])
        assert result == 0
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_changed_file_linted(self, tmp_path, capsys):
        """--changed with one modified .py → that file is linted."""
        root = _make_lint_project(tmp_path)
 
        # Modify the committed file.
        path = root / "src" / "ok.py"
        path.write_text(path.read_text(encoding="utf-8") + "\ny = 2\n", encoding="utf-8")
 
        from oct.linter.oct_lint import run_linter
        run_linter(root, ["--changed"])
        captured = capsys.readouterr()
        # Should mention the modified file.
        assert "ok.py" in captured.out or "1" in captured.out
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_non_py_changes_filtered(self, tmp_path):
        """--changed with only non-.py modifications → no files to lint."""
        root = _make_lint_project(tmp_path)
        (root / "README.md").write_text("# readme\n", encoding="utf-8")
 
        from oct.linter.oct_lint import run_linter
        result = run_linter(root, ["--changed"])
        assert result == 0
 
    def test_non_git_dir_graceful(self, tmp_path):
        """--changed on a non-git directory → graceful empty result."""
        root = tmp_path / "nongit"
        root.mkdir()
        (root / "pyproject.toml").write_text(
            '[project]\nname = "nongit"\n', encoding="utf-8",
        )
        (root / "src").mkdir()
        (root / "src" / "x.py").write_text("x = 1\n", encoding="utf-8")
 
        from oct.linter.oct_lint import run_linter
        result = run_linter(root, ["--changed"])
        assert result == 0
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_changed_json_output(self, tmp_path, capsys):
        """--changed --json produces valid JSON."""
        root = _make_lint_project(tmp_path)
        path = root / "src" / "ok.py"
        path.write_text(path.read_text(encoding="utf-8") + "\nz = 3\n", encoding="utf-8")
 
        from oct.linter.oct_lint import run_linter
        run_linter(root, ["--changed", "--json"])
        captured = capsys.readouterr()
        data = json.loads(captured.out)
        assert isinstance(data, dict)
        assert "files" in data or "summary" in data