CONTRIBUTING.md

How to contribute

Do you have questions or issues? Join our chat!

Tutorials

If you want to start working on this project, you will need to get familiar with these concepts:

• http://learnyouahaskell.com/functors-applicative-functors-and-monoids
• https://github.com/dbrattli/OSlash/wiki/Functors,-Applicatives,-And-Monads-In-Pictures
• https://gcanti.github.io/fp-ts/ and https://dev.to/gcanti

Here are some practical examples of what we are doing here:

• https://medium.com/@rnesytov/using-Result-monad-in-python-b6eac698dff5
• https://www.morozov.is/2018/09/08/monad-laws-in-ruby.html
• https://beepb00p.xyz/mypy-error-handling.html

Dependencies

We use poetry to manage the dependencies.

To install them you would need to run the install command:

poetry install

To install extra dependencies for working on the hypothesis or mypy plugin:

poetry install --extras check-laws
poetry install --extras compatible-mypy

To activate your virtualenv run eval $(poetry env activate).

Tests

We use pytest and flake8 for quality control. We also use wemake_python_styleguide to enforce code quality.

To run standard tests:

poetry run pytest returns docs/pages tests

NOTE: type-safety tests not included, see section on type tests below

To run linting:

poetry run flake8 .

Keep in mind: default virtual environment folder excluded by flake8 style checking is .venv. If you want to customize this parameter, you should do this in setup.cfg.

These steps are mandatory during CI.

Type tests

We also use pytest-mypy-plugins. Tests cases are located inside ./typesafety If you create new types or typed functions, it is required to test their types.

The type-safety tests can be run with the following:

poetry run pytest typesafety

NOTE: This can take upwards of 20 minutes, only recommended to run if necessary.

Here's a helpful tutorial if you are looking for more information.

Type checks

We use mypy to run type checks on our code. To use it:

poetry run mypy returns tests/**/*.py

This step is mandatory during CI.

Submitting your code

We use trunk based development (we also sometimes call it wemake-git-flow).

What the point of this method?

1. We use protected master branch, so the only way to push your code is via pull request
2. We use issue branches: to implement a new feature or to fix a bug create a new branch named issue-$TASKNUMBER
3. Then create a pull request to master branch
4. We use git tags to make releases, so we can track what has changed since the latest release

So, this way we achieve an easy and scalable development process which frees us from merging hell and long-living branches.

In this method, the latest version of the app is always in the master branch.

Before submitting

Before submitting your code please do the following steps:

1. Run pytest to make sure everything was working before
2. Add any changes you want
3. Add tests for the new changes
4. Edit documentation if you have changed something significant
5. Update CHANGELOG.md with a quick summary of your changes
6. Run pytest again to make sure it is still working
7. Run mypy to ensure that types are correct
8. Run flake8 to ensure that style is correct
9. Run slotscheck to ensure that slots are correct

Other help

You can contribute by spreading a word about this library. It would also be a huge contribution to write a short article on how you are using this project. You can also share your best practices with us.

Join in the conversation with us on our Telegram.