pytest-mirror

A pluggy-based pytest plugin and CLI tool for ensuring your test suite mirrors your source code structure.

Overview

pytest-mirror helps you:

• Ensure every Python module in your package has a corresponding test file.
• Quickly generate missing test stubs for new or existing code.
• Validate that your test suite structure matches your package structure.
• Integrate with pytest as a plugin or use as a standalone CLI.

Built with pluggy for extensible plugin architecture.

Features

• Test Structure Validation: Checks for missing test files that should correspond to your package modules.
• Test Stub Generation: Automatically creates test files and __init__.py as needed, with a failing test stub.
• CLI and Plugin: Use as a command-line tool or as a pytest plugin.
• Customizable: Specify package and test directories.

Installation

pip install pytest-mirror

For local development:

# Clone the repository and install in development mode
git clone https://github.com/dvonpasecky/pytest-mirror.git
cd pytest-mirror
pip install -e .

Or with uv:

uv sync

Usage

CLI

# With explicit directories:
pytest-mirror generate --package-dir src/your_package --tests-dir tests
pytest-mirror validate --package-dir src/your_package --tests-dir tests

# Or let pytest-mirror auto-detect your package and tests directories:
pytest-mirror generate
pytest-mirror validate

• generate: Creates missing test files for all modules in your package.
• validate: Checks for missing test files and reports any discrepancies.

As a pytest Plugin

Add pytest-mirror to your test dependencies. The plugin will automatically:

1. Validate your test structure when running pytest
2. Auto-generate missing test files (unless disabled)

pytest

Plugin Configuration

You can customize the plugin behavior using:

• Command-line flags:
  • --mirror-package-dir (path to your package)
  • --mirror-tests-dir (path to your tests)
  • --mirror-no-generate (disable automatic test generation)

If package and tests directories are not specified, the plugin will auto-detect the most likely directories.

Auto-generation behavior: By default, the plugin will automatically create missing test files when pytest runs. Use --mirror-no-generate to disable this and only validate structure.

API

You can also use the core functions in your own scripts:

from pytest_mirror import generate_missing_tests, find_missing_tests

# Generate missing test files
generate_missing_tests('src/your_package', 'tests')

# Find missing test files without creating them
missing = find_missing_tests('src/your_package', 'tests')
print(missing)

Development

• All code is in src/pytest_mirror/.
• Tests are in tests/ with 1:1 module mirroring.
• Run tests with:

pytest
# or with uv:
uv run pytest

• Lint and check style with:

ruff check src/ tests/
# or with uv:
uv run ruff check src/ tests/

Contributing

Contributions are welcome! Please:

• Add or update tests for your changes.
• Ensure all tests and linters pass.
• Update this README if needed.

License

MIT License. See LICENSE.

This project is not affiliated with pytest or pluggy, but is built to extend and complement them.