1. Clone the repo: git clone git@github.com:python-lsp/python-lsp-server.git
2. Create the virtual environment: python -m venv .venv
3. Activate: source .venv/bin/activate
4. Install an editable installation: pip install -e .
   • This will ensure you'll see your edits immediately without reinstalling the project
5. Configure your editor to point the pylsp executable to the one in .venv

Go to file pylsp/python_lsp.py, function start_io_lang_server, and on the first line of the function, add some logging:

log.info("It works!")

Save the file, restart the LSP server and you should see the log line:

2023-10-12 16:46:38,320 CEST - INFO - pylsp._utils - It works!

Now the project is setup in a way you can quickly iterate change you want to add.

1. Install runtime dependencies: pip install .[all]
2. Install test dependencies: pip install .[test]
3. Run pytest: pytest -v

• To run a specific test file, use pytest test/test_utils.py
• To run a specific test function within a test file, use pytest test/test_utils.py::test_debounce
• To run tests matching a certain expression, use pytest -k format
• To increase verbosity of pytest, use pytest -v or pytest -vv
• To enter a debugger on failed tests, use pytest --pdb