How to contribute

First, thanks for considering contributing to Astrality, that means a lot! Here we describe how you can help out, either by improving the documentation, submitting issues, or creating pull requests.

If you end up contributing, please consider adding yourself to the file CONTRIBUTORS.rst.

Bug reports and feature requests

You can browse any existing bug reports and feature requests on Astrality’s GitHub issues page on GitHub. New issues issues can be submitted the GitHub create issues page.

Improving the documentation

If you find something you would like to improve in the documentation, follow these steps:

  • Navigate to the page that you would like to edit on
  • Press the “Edit on GitHub” link in the upper right corner.
  • Press the “pencil” edit icon to the right of the “History” button.
  • Make the changes you intended.
  • Write a title and description for your change on the bottom of the page.
  • Select the radio button marked as: “Create a new branch for this commit and start a pull request”.
  • Press “Propose file change”.

The documentation is written in the “RestructuredText” markup language. If this is unfamiliar to you, take a look at this RST cheatsheet for more information.

Contributing code

Getting up and running

Cloning the repository

First we need to clone the repository. Open your terminal and navigate to the directory you wish to place project directory and run:

git clone
cd astrality

Installing python3.6

Astrality runs on python3.6, so you need to ensure that you have it installed. If you have no specific preferred way of installing software on your computer, you can download and install it from here. Alternatively, if you use brew on MacOS, you can install it by running:

brew install python3

Or on ArchLinux:

sudo pacman -S python

Installing dependencies into a virtual environment

You should create a separate python3.6 “virtual environment” exclusively for Astrality. If this is new to you, take a look at the official virtualenv tutorial.

A quick summation:

python3.6 -m venv astrality-env
source astrality-env/bin/activate

Your terminal prompt should now show the name of the activated virtual environment, for example (astrality-env) $ your_commands_here. You can double check your environment by running echo $VIRTUAL_ENV. Later you can deactivate it by running deactivate or restarting your terminal. The activated virtual environment is necessary in order to run the developer version of Astrality, including the test suite.

Now you can install all the developer dependencies of Astrality into the virtual environment by running:

pip3 install -r requirements.txt

You should now make sure that the environment variable PYTHONPATH is set to the root directory of the repository. Check it by running:


With /home/jakobgm/dev/astrality being whatever makes sense on your system. If the value is incorrect you should run the following from the repository root:

export PYTHONPATH=$(pwd)

Running the developer version of Astrality

You should now be able to run the developer version of Astrality by running the following command:


Writing code

The python code in Astrality follows some conventions which we will describe here.

The structure of the code base

A brief outline Astrality’s code base is provided in the API documentation, and is recommended reading for any new contributor.


Astrality strives for 100% test coverage, and all new lines of code should preferably be covered by tests. That being said, if testing is unfamiliar to you, submitting code without test coverage is better than no code at all.

Tests are written with the pytest test framework, and you can read a “getting started” tutorial here.

You can run the test suite from the root of the repository by running:



For now, it is important that you run pytest from the root of the repository, else you will get a whole lot of ModuleNotFoundError exceptions.

Additionally, there are some tests which are hidden behind the --runslow flag, as some tests are slow due to writing files to disk and running certain shell commands. These slow tests can be run by writing:

pytest --runslow

When you submit a pull request, travis-ci will automatically check if all the tests pass with your submitted code. Coveralls will also check if the test coverage decreases.

If this feels intimidating, do not worry. We are happy to help guide you along if you encounter any issues with testing, so please submit pull requests even if the test suite fails for some reason.

Type annotations

Astrality’s code base heavily utilizes the new static type annotations available in python3.6.

The correctness of the type annotations are ensured by using mypy. You can check for type errors by running the following command from the repository root:

mypy .

mypy is a part of the test suite, enabled by the pytest-mypy plugin. Therefore, if the test suite passes, mypy must also be satisfied with your code!

All non-testing code should be completely type annotated, as strictly as possible. If this is new to you, or if you want to learn more, I recommend reading mypy documentation.

The offer to help with testing also holds for type annotations of course!

Continuous testing

Although this is mainly a matter of taste, running tests continuously while writing code is a great feedback mechanism.

pytest-watch should be already be installed on your system as part of Astrality’s developer dependencies. You can use it to rerun the test suite every time you save any *.py file within the repository.

You can run it in a separate terminal by running:


It is often useful to run pytest-watch in verbose mode, stop on first test failure, and only run one specific test file at a time. You can do all this by running:

ptw -- -vv -x astrality/tests/


If you end up breaking any behaviour during development, it should often be reported by the test suite. Breaking tests will often lead you in the correct direction for fixing the problem.

Some tests might be a bit too brittle, so if you change any underlying data structures it might break some badly written test(s). Sometimes the correct thing to do is to simply delete the failing test. Just ask if you are unsure.

You can also look at the logging output of Astrality in order to pinpoint possible reasons for any weird behaviour. You can set the logging level of astrality by setting the environment variable ASTRALITY_LOGGING_LEVEL to an appropriate value, for example:

# Set the appropiate logging level

# Run the CLI entrypoint

If you submit a bug report, we appreciate if you include the standard output of Astrality run with ASTRALITY_LOGGING_LEVEL=DEBUG.

Code style

We use the python source code checker flake8 to help us maintain a consistent style across the code base. It runs automatically as part of our pytest test-suite.

You can lint your code locally by running flake8 . from the root of the repository. Integrating flake8 into your workflow is recommended, there are plugins available for most popular IDEs and text-editors!

You can instruct git to ensure flake8 compliance before every commit by running git config --bool flake8.strict true from your shell.

In addition to this, some additional styling conventions are applied to the project:

  • String literals should use single quotes. With other words: 'this is a string' instead of "this is a string".

  • Try to use keyword arguments when calling functions, unless it is extremely clear from context.

  • Function arguments split over several lines should use trailing commas. With other words, we prefer to write code like this:


    Instead of this:


These conventions are mainly enforced in order to stay consistent for choices where PEP 8 do not tell us what to do.

Local documentation

Astrality uses the sphinx ecosystem in conjunction with readthedocs for its documentation.

You can run a local instance of the documentation by running:

cd docs
sphinx-autobuild . _build

The entire documentation should now be available on When you edit the documentation files placed with docs, your web browser should automatically refresh the website with the new content!