test_import_fixing.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_formatter/test_import_fixing.py
 
"""
Tests for import fixing.
 
Purpose
-------
Verify that the formatter correctly fixes _dbg import issues.
 
Responsibilities
----------------
- Test addition of canonical _dbg import when missing.
- Test removal of aliased/incorrect imports.
- Test correct placement after header block.
- Test preservation of other imports.
 
Diagnostics
-----------
Domain: TESTS.FORMATTER
Levels:
    L2 — test lifecycle
    L3 — test case setup
    L4 — detailed import parsing and verification
 
Contracts
---------
- Canonical form is: from oc_diagnostics import _dbg
- Import must be at module level (after header block).
- Trivial files (< 20 lines) are skipped.
- Other imports are preserved.
"""
 
import pytest
from pathlib import Path
 
from oct.formatter.oct_format import fix_dbg_import, FormatterContext
 
 
# Helper to create a file with enough lines to not be trivial
def _make_nontrivial(content: str) -> str:
    """Pad content to be > 20 lines."""
    lines = content.split('\n')
    while len(lines) < 22:
        lines.append("# padding")
    return '\n'.join(lines)
 
 
def test_add_missing_import(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that canonical import is added when missing."""
    test_file = temp_project_root / "test_missing_import.py"
    content = _make_nontrivial(
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# test.py\n"
        "\n"
        "def foo():\n"
        "    _dbg('TEST', 'test')\n"
    )
    test_file.write_text(content, encoding="utf-8")
 
    changed, new_content, messages = fix_dbg_import(test_file, content, formatter_ctx_fix)
 
    assert changed is True
    assert "from oc_diagnostics import _dbg" in new_content
 
 
def test_skip_trivial_files(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that trivial files (< 20 lines) are skipped."""
    test_file = temp_project_root / "test_trivial.py"
    content = "# No imports\ndef foo():\n    pass\n"
    test_file.write_text(content, encoding="utf-8")
 
    changed, _, messages = fix_dbg_import(test_file, content, formatter_ctx_fix)
 
    assert changed is False
 
 
def test_import_dry_run(temp_project_root: Path, formatter_ctx: FormatterContext):
    """Test that dry-run mode doesn't modify files."""
    test_file = temp_project_root / "test_import_dryrun.py"
    content = _make_nontrivial(
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# test.py\n"
        "\n"
        "def foo():\n"
        "    _dbg('TEST', 'test')\n"
    )
    test_file.write_text(content, encoding="utf-8")
 
    changed, _, messages = fix_dbg_import(test_file, content, formatter_ctx)
 
    assert changed is True  # Change detected
    assert test_file.read_text(encoding="utf-8") == content  # But not applied
 
 
def test_canonical_import_no_change(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that canonical imports are not modified."""
    test_file = temp_project_root / "test_canonical_import.py"
    content = _make_nontrivial(
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# test.py\n"
        "\n"
        "from oc_diagnostics import _dbg\n"
        "\n"
        "def foo():\n"
        "    _dbg('TEST', 'test')\n"
    )
    test_file.write_text(content, encoding="utf-8")
 
    changed, _, messages = fix_dbg_import(test_file, content, formatter_ctx_fix)
 
    assert changed is False
 
 
def test_preserve_other_imports(temp_project_root: Path, formatter_ctx_fix: FormatterContext):
    """Test that other imports are preserved."""
    test_file = temp_project_root / "test_preserve_imports.py"
    content = _make_nontrivial(
        "#!/usr/bin/env python3\n"
        "# -*- coding: utf-8 -*-\n"
        "# test.py\n"
        "\n"
        "import sys\n"
        "import os\n"
        "\n"
        "def foo():\n"
        "    _dbg('TEST', 'test')\n"
    )
    test_file.write_text(content, encoding="utf-8")
 
    changed, new_content, messages = fix_dbg_import(test_file, content, formatter_ctx_fix)
 
    assert changed is True
    assert "import sys" in new_content
    assert "import os" in new_content
    assert "from oc_diagnostics import _dbg" in new_content