test_format_changed.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_formatter/test_format_changed.py
 
"""
Purpose
-------
Tests for ``oct format --changed`` (Phase 4C — G-C2).
 
Responsibilities
----------------
- Verify that ``--changed`` formats only git-modified Python files.
- Verify graceful behaviour in non-git directories.
- Verify JSON output mode with ``--changed``.
 
Diagnostics
-----------
Domain: FMT-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_format_project(tmp_path: Path) -> Path:
    """Create a git repo with pyproject.toml and one committed Python file."""
    root = tmp_path / "fmtproj"
    root.mkdir()
    (root / "src").mkdir()
    (root / "tests").mkdir()
    (root / "docs").mkdir()
    (root / "oc_diagnostics").mkdir()
    (root / "pyproject.toml").write_text(
        '[project]\nname = "fmtproj"\n', encoding="utf-8",
    )
 
    # Write a compliant file and commit.
    compliant = textwrap.dedent("""\
        #!/usr/bin/env python3
        # -*- coding: utf-8 -*-
        # src/clean.py
 
        \"\"\"
        Purpose
        -------
        A clean 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" / "clean.py").write_text(compliant, 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 TestFormatChanged:
 
    @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 files."""
        root = _make_format_project(tmp_path)
        from oct.formatter.oct_format import run_formatter
        # Should return None (no files to format, early exit).
        result = run_formatter(root, ["--changed"])
        assert result is None
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_changed_file_processed(self, tmp_path, capsys):
        """--changed with one modified file → that file is formatted."""
        root = _make_format_project(tmp_path)
 
        # Modify the committed file (make it dirty).
        dirty = (root / "src" / "clean.py").read_text(encoding="utf-8")
        (root / "src" / "clean.py").write_text(dirty + "\ny = 2\n", encoding="utf-8")
 
        from oct.formatter.oct_format import run_formatter
        run_formatter(root, ["--changed"])
        captured = capsys.readouterr()
        # Should mention 1 file processed.
        assert "1" in captured.out or "clean.py" in captured.out
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_unchanged_files_skipped(self, tmp_path, capsys):
        """--changed should NOT process files without modifications."""
        root = _make_format_project(tmp_path)
 
        # Add a new file (modified) but leave clean.py untouched.
        new_file = root / "src" / "added.py"
        new_file.write_text("# added\nx = 1\n", encoding="utf-8")
 
        from oct.formatter.oct_format import run_formatter
        run_formatter(root, ["--changed"])
        captured = capsys.readouterr()
        # Output should only mention the added file, not clean.py.
        assert "clean.py" not in captured.out or "1" in captured.out
 
    @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_format_project(tmp_path)
        dirty = (root / "src" / "clean.py").read_text(encoding="utf-8")
        (root / "src" / "clean.py").write_text(dirty + "\nz = 3\n", encoding="utf-8")
 
        from oct.formatter.oct_format import run_formatter
        run_formatter(root, ["--changed", "--json"])
        captured = capsys.readouterr()
        data = json.loads(captured.out)
        assert "files" in data
        assert isinstance(data["files"], list)
 
    def test_non_git_dir_graceful(self, tmp_path, capsys):
        """--changed on a non-git directory → graceful empty result."""
        root = tmp_path / "nogit"
        root.mkdir()
        (root / "pyproject.toml").write_text(
            '[project]\nname = "nogit"\n', encoding="utf-8",
        )
        (root / "src").mkdir()
        (root / "src" / "x.py").write_text("x = 1\n", encoding="utf-8")
 
        from oct.formatter.oct_format import run_formatter
        result = run_formatter(root, ["--changed"])
        assert result is None
 
    @pytest.mark.skipif(not _git_available(), reason="git not on PATH")
    def test_changed_fix_applies(self, tmp_path):
        """--changed --fix should apply fixes only to changed files."""
        root = _make_format_project(tmp_path)
 
        # Create a file without a proper header (needs fix).
        bad = root / "src" / "bad.py"
        bad.write_text("# bad file\nx = 1\n", encoding="utf-8")
 
        from oct.formatter.oct_format import run_formatter
        run_formatter(root, ["--changed", "--fix"])
        content = bad.read_text(encoding="utf-8")
        # After fix, should have shebang line.
        assert "#!/usr/bin/env python3" in content