Behind the Scenes of tox: The Journey of Rewriting a Python Tool with more than 10 Million Monthly Downloads
2023-04-19 , Kuppelsaal

tox is a widely-used tool for automating testing in Python. In this talk, we will go behind the scenes of the creation of tox 4, the latest version of the tool. We will discuss the motivations for the rewrite, the challenges and lessons learned during the development process. We will have a look at the new features and improvements introduced in tox 4. But most importantly, you will get to know the maintainers.


Do you recall what developer legend Joel Spolsky called the "single worst strategic mistake" in "Things You Should Never Do"?

Rewriting software from scratch.

That is what we did. For the tox test automation tool. A tool, downloaded more than 10 million times a month, both heavily used in the open source community, and in multi-billion dollar companies alike.

I invite you to join me on the very personal journey of rewriting tox, a journey, which already started in 2019. We will have a look at the initial motivations for the rewrite, the design decisions, the challenges, and the lessons learned.

We will reconstruct why it took more than three years, from the idea to the release, and why this was a good thing.

I will explain what we did to take care that the release would cause the least amount of issues, and why we still received dozens and dozens of bug reports about regressions the days after the release.

And finally, I will answer the question. Was it worth it?


Expected audience expertise: Domain:

Novice

Expected audience expertise: Python:

Novice

Abstract as a tweet:

Behind the Scenes of tox: The Journey of Rewriting a Python Tool with Over 10 Million Monthly Downloads

I am a software developer with a passion for Python and Linux, developing open source software both at my day job at Canonical, and at night as a maintainer of tox and many other projects.