Overview

jest-pytest is a way to use Jest, the test platform from Facebook, with Pytest - a popular Python test infrastructure.

If you're a Pythonista, using Jest with Python will unlock a modern, cutting-edge testing experience for your workflow, making your tests run faster and welcoming you to join the huge amount of people already using Jest for their front-end, React and Node.js workflows.

How it Works

Essentially jest-pytest is a couple modules, each taking care of the two sides: Javascript (Jest), and Python (Pytest). We install them both.

First the Pytest plugin:

$ pip install pytest-jest

For Python, I've used pip directly, but feel free to use pipenv / poetry / flit and so on, what ever you prefer to maintain dependencies. Pytest will pick this plugin up once it exists in your environment.

And then our Pytest Jest runner:

$ yarn add --dev jest-pytest

If you don't have a package.json set up, here's how:

$ yarn init && yarn add --dev jest

Finally, we'll configure our project to use this runner and let Jest know how to find tests (some use the pattern test_*.py and some prefer *_test.py, what ever it is - we can configure it).

"jest": {
    "moduleFileExtensions": ["py"],
    "runner": "jest-pytest",
    "testPathIgnorePatterns": [],
    "testMatch": ["**/test_*.py"]
}

Done!

Using Jest

I can't recommend enough to look at the Jest website, because this tool has a lot to offer; not only you unlock a great development experience but a whole community and extra tooling.

Either way, here's a quick starter for you to use. To run your test normally:

$ yarn jest

To run in interactive mode (if you're unfamiliar with Jest, this will be mind blowing):

$ yarn jest --watch

Go forth and experiment!