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:microscope: Table of Contents

Internals

Welcome to the developer documentation for pyatv, i.e. the documentation explaining how pyatv works (internally) and how to extend it. This section used to reside in the GitHub wiki, but has moved to the general documentation for greater availability. It is still under heavy development, so beware of missing and/or outdated content as it is migrated from the wiki.

Setting up a New Environment

Linux/macOS/*NIX

You can run the script scripts/setup_dev_env.sh to set up a complete development environment. It will make sure that everything works as expected by running tox, building documentation (with docker), etc.

$ ./scripts/setup_dev_env.sh

Windows

There’s no helper script for windows, but you can get started manually like this:

$ git clone https://github.com/postlund/pyatv.git
$ cd pyatv
$ python3 -m venv venv
$ source venv/Scripts/activate
$ python setup.py develop
$ pip install tox
$ pip install -r requirements_test.txt
$ tox

Testing Changes

If you followed the instructions above, then pyatv will be installed as “develop”. This means that you can keep doing updates without having to do python setup.py install between changes.

Testing with tox

To test everything, just run tox:

$ tox -p auto

This will make sure that tests pass, you have followed coding guidelines (pylint, flake8, etc), verify protobuf messages and generate coverage data. You can run steps individually as well:

What Command
Unit tests tox -e py{35,36,37,38}
Code style tox -e codestyle
pylint tox -e pylint
Generated Code tox -e generated
Documentation tox -e docs

Note: pylint should technically be part of codestyle but has been extracted to its own environment to increase parallelization.

If you change required version for, add or remove a dependency you should pass -r to tox to force it to re-create the environment (once). Otherwise your changes will not be reflected.

Generally, tox will install the latest version of all dependencies when setting up new environments. There’s however a special environment called regression, which will install the “lowest versions” of all dependencies (that pyatv is supposed to work with) and run checks with those. Generally you will not need to run that by yourself, but sometimes you might find that it breaks when GitHub Actions runs it.

Base versions used by regression are in base_versions.txt.

Updating protobuf Definitions

If you have made changes to the protobuf messages in pyatv/mrp/protobuf, you can make sure everything is updated by running:

$ ./scripts/protobuf.py --download generate

See Protobuf for more details.

Running Tests

Recommended way to run unit tests:

$ pytest --log-level=debug --disable-warnings

Warnings are disabled because of deprecated loop argument in lots of places. This flag will be lifted eventually. See Testing for details regarding tests.

Re-formatting code

All python code is formatted using black, so you don’t have to care about how the code looks. Just let black take care of it:

$ black .
All done! ✨ 🍰 ✨
77 files left unchanged.

Code formatting is checked by tox, so it’s not possible to check in code if it doesn’t comply with black.

Documentation

NB: This step currently requires docker and is only tested on Linux!

To serve a local running web server that performs incremental updates of the documentation, run:

$ ./scripts/build_doc.sh

Navigate to http://localhost:4000 to see the result.

The lint environment (tox -e lint) will do basic spell checking of the documentation (and code) using codespell.

Cheat Sheet

Here are a few convenient commands in short form:

Command What
pytest –disable-warnings –log-level=debug -k XXX Run tests matching XXX
black . Re-format code with black
./scripts/protobuf.py –download generate Update protobuf definitions
./scripts/build_doc.sh Serve web server with documentation at http://127.0.0.1:4000
./scripts/api.sh generate Update generate API documentation in docs/api
./scripts/features.sh Generate pyatv.const.FeatureName (you need to copy-paste it) and print next free index
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