test_regression.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_linter/test_regression.py
 
"""
Purpose
-------
Ensure previously fixed bugs never reappear.
 
Responsibilities
----------------
- Test scenarios that historically caused linter failures.
- Validate docstring preservation.
- Validate encoding preservation.
- Validate correct handling of tricky edge cases.
 
Diagnostics
-----------
Domain: LINTER-TESTS
Levels:
    L2 — lifecycle
    L3 — semantic details
    L4 — deep tracing
 
Contracts
---------
- Must encode each regression as a permanent test.
- Must ensure fixes remain stable across refactors.
- Must not modify fixture files.
"""
 
from pathlib import Path
from oct.linter import oct_lint
 
 
def test_docstring_not_overwritten(temp_project_root: Path, linter_ctx: oct_lint.LinterContext):
    fixture = temp_project_root / "tests_linter" / "fixtures" / "header_below_docstring.py"
    original = fixture.read_text(encoding="utf-8")
 
    oct_lint.fix_header_block(fixture, original, linter_ctx)
    text = fixture.read_text(encoding="utf-8")
 
    assert '"""' in text.splitlines()[4:], "Docstring should remain after header block"
    assert "Header below docstring." in text
 
 
def test_encoding_not_overwritten(temp_project_root: Path, linter_ctx: oct_lint.LinterContext):
    fixture = temp_project_root / "tests_linter" / "fixtures" / "unicode_content.py"
    original = fixture.read_text(encoding="utf-8")
 
    oct_lint.fix_header_block(fixture, original, linter_ctx)
    lines = fixture.read_text(encoding="utf-8").splitlines()
 
    assert lines[1].strip() == oct_lint.ENCODING
    assert "MIDI 🎵 Bridge" in fixture.read_text(encoding="utf-8")