test_header_fixing.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_formatter/test_header_fixing.py
 
"""
Tests for header block fixing.
 
Purpose
-------
Verify that the formatter correctly fixes malformed header blocks.
 
Responsibilities
----------------
- Test missing shebang fixes.
- Test missing encoding fixes.
- Test incorrect file identity fixes.
- Test missing blank line fixes.
- Verify archival of original files.
- Verify code preservation.
 
Diagnostics
-----------
Domain: TESTS.FORMATTER
Levels:
    L2 — test lifecycle
    L3 — test case setup
    L4 — detailed assertion checks
 
Contracts
---------
- All tests verify that fix_header_block returns (True, new_text, messages) when changes are needed.
- All tests verify that original files are archived before modification.
"""
 
import pytest
from pathlib import Path
 
from oct.formatter.oct_format import fix_header_block, FormatterContext
 
 
def test_fix_missing_shebang(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that missing shebang is added correctly."""
    test_file = temp_project_root / "test_missing_shebang.py"
    test_file.write_text(
        "# -*- coding: utf-8 -*-\n"
        "# test.py\n"
        "\n"
        "print('hello')\n",
        encoding="utf-8"
    )
 
    changed, new_text, messages = fix_header_block(test_file, test_file.read_text(encoding="utf-8"), formatter_ctx_fix)
 
    assert changed is True
    assert len(messages) > 0
    assert new_text.startswith("#!/usr/bin/env python3\n")
 
 
def test_fix_missing_encoding(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that missing encoding is added correctly."""
    test_file = temp_project_root / "test_missing_encoding.py"
    test_file.write_text(
        "#!/usr/bin/env python3\n"
        "# test.py\n"
        "\n"
        "print('hello')\n",
        encoding="utf-8"
    )
 
    changed, new_text, messages = fix_header_block(test_file, test_file.read_text(encoding="utf-8"), formatter_ctx_fix)
 
    assert changed is True
    lines = new_text.split('\n')
    assert lines[1] == "# -*- coding: utf-8 -*-"
 
 
def test_fix_wrong_path_header(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that incorrect file path header is rewritten."""
    test_file = temp_project_root / "test_wrong_path.py"
    test_file.write_text(
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# wrong/path/to/file.py\n"
        "\n"
        "print('hello')\n",
        encoding="utf-8"
    )
 
    changed, new_text, messages = fix_header_block(test_file, test_file.read_text(encoding="utf-8"), formatter_ctx_fix)
 
    assert changed is True
    lines = new_text.split('\n')
    assert "test_wrong_path.py" in lines[2]
 
 
def test_header_archives_original(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that format_file archives original before writing (archival moved to format_file)."""
    from oct.formatter.oct_format import format_file
    test_file = temp_project_root / "test_archive.py"
    original_content = (
        "# Missing header\n"
        "print('hello')\n"
    )
    test_file.write_text(original_content, encoding="utf-8")
 
    result = format_file(test_file, formatter_ctx_fix)
 
    assert result["changed"] is True
    archive_dir = test_file.parent / ".formatter_archive"
    assert archive_dir.exists()
    backups = list(archive_dir.glob("test_archive.py.*"))
    assert len(backups) == 1
    assert backups[0].read_text(encoding="utf-8") == original_content
 
 
def test_header_preserves_code(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that code below header is preserved exactly."""
    test_file = temp_project_root / "test_preserve.py"
    code_content = """def my_function():
    '''
    Multi-line
    docstring
    '''
    x = 1
    y = 2
    return x + y
"""
    test_file.write_text(
        "# Missing header\n"
        + code_content,
        encoding="utf-8"
    )
 
    changed, new_text, messages = fix_header_block(test_file, test_file.read_text(encoding="utf-8"), formatter_ctx_fix)
 
    assert changed is True
    assert code_content in new_text
 
 
def test_header_dry_run_no_modify(temp_project_root: Path, formatter_ctx: FormatterContext):
    """Test that dry-run mode doesn't modify files."""
    test_file = temp_project_root / "test_dryrun.py"
    original_content = "# Missing header\nprint('hello')\n"
    test_file.write_text(original_content, encoding="utf-8")
 
    changed, _, messages = fix_header_block(test_file, original_content, formatter_ctx)
 
    assert changed is True  # Changed is detected
    assert test_file.read_text(encoding="utf-8") == original_content  # But file not modified
 
 
def test_header_correct_no_change(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that correct headers are not modified."""
    test_file = temp_project_root / "test_correct.py"
    correct_content = (
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# test_correct.py\n"
        "\n"
        "print('hello')\n"
    )
    test_file.write_text(correct_content, encoding="utf-8")
 
    changed, _, messages = fix_header_block(test_file, correct_content, formatter_ctx_fix)
 
    assert changed is False
    assert len(messages) == 0