pedalboard VS nyc

You can check out some demo examples in this Storybook, and see the code in the pedalboard repo.

Turns out there are tools for that and one of them is called typescript-coverage-report by Alex Canessa and I’m going to give it a try now and implement it in my Pedalboard monorepo.

Also, all the code mentioned here can be found in the GitHub repository for this plugin. Put your testing helmet on, here we go!

My Components package currently supports regular plain-old CSS (not that there’s anything wrong with it), and I thought it was a good time to introduce SASS to it, but the package is not a ordinary “Webpack-build-that-s#!t-for-me”. I’m using TSC (TypeScript Compiler) to generate the artifacts - What it means is that TSC is compiling 2 versions of the component, ESM and CJS. Once we have these, we’re taking the ESM outcome and bundling it using esbuild. You can read more about it here, but if to put it visually:

In this post I will write a test suite for my @pedalboard/stylelint-plugin-craftsmanlint. We will be using jest-preset-stylelint to help us with that, and as a bonus, I’ll fortify the plugin’s TypeScript support.

For reference, below is an image of the Pagination component, and you can find it’s code here:

Disclaimer - I’m going to apply the following steps on my Pedalboard monorepo. Working with monrepos is a bit different, and I will relate to that during the process, but be aware that applying Chromatic on a “simple” repo is even simpler.

I have noticed that although the build process for packages under my “pedalboard” Monorepo creates different artifacts (CJS, ESM and types - you can read about it in more details in my “Hybrid NPM package through TypeScript Compiler (TSC)” post) it does not create a single bundle for the entire package.

I will attempt to introduce this visual regression testing to my Pagination component from the @pedalboard/components package. So here we go.

So let’s see how this tool works and what we can do with it. I’m gonna do my experimenting over my Pagination component which resides on the @pedalboard/components package. Let’s go!

Native code coverage via v8 or istanbul.

Writing tests is essential, and knowing whether you test all the required cases for your logic is even more critical. The most common testing coverage tool is Istanbul, where you can see how well your tests exercise your code by lines, functions, and branches. Below is an example of how the test coverage report looks in your terminal:

Here is a quote from istanbul, one of the most used code coverage tool:

Unit testing framework was already implemented, using Vitest so I started hacking by setting up a coverage provider to explicitly identify the covered/uncovered lines and mentioned this to the maintainer in the comments. I used Istanbul 🇹🇷 for this purpose.

Your project probably has a coverage report. If you’re using Jest as your unit test runner, generating a coverage report is embedded in it. It is done with Istanbul under the hood, which generates a nice HTML page presenting the entire project unit test coverage.

> This is a rant written by someone with just enough understanding to be dangerous, but not quite enough wisdom to know why things are still the way they are. Most of the complaints raised are subtly inaccurate.

Author seems aware of CAP_NET_BIND_SERVICE: https://source.small-tech.org/site.js/app/-/issues/169 and https://github.com/istanbuljs/nyc/issues/1281 – the "side effects" are NodeJS explicitly checking for it, so that's a NodeJS thing and not a Linux thing.

Yet curiously it's completely unmentioned in this article, in spite that this is probably what started the author's dislike of privileged ports. I guess it was inconvenient as it got in the way of angrily ranting.

This approach will create two json coverage files, which will be merged together by NYC. Therefore the results will be purely local. If You don't mind using online tools like Codecov or Coveralls for merging data from different tests, then go ahead and use them. They will probably also be more accurate. But if You still want to learn how to get coverage from E2E, then please read through

https://istanbul.js.org/ measures how much of your code is covered by tests

Jest uses a package called Istanbul to provide test coverage metrics such as statement, branch, function, and line coverage so that you can understand and enforce the quality of your test suite, providing more confidence in releases.

So let’s see if nyc (the code coverage generator) can help with that. Hmm… this documentation seems interesting! So basically what I understand from it is that I need to collect all the reports from the different packages and then run the nyc report over it. The flow should be like this: