Post Jest results into Github PRs

At BodyFast we recently decided to migrate out of Bitrise for our javascript tests, that means, we continue to use Bitrise for building our react-native app but all other tests (jest, lint, flow, tsc) are now running on github actions

Why leave Bitrise

Bitrise is good because the amount of available workflows and steps and how you can chain them to create your CI workflow, however, it is really slow and it also expensive for faster build machines.

Even though we are already on a medium plan, we started having queueing slow downs, our app takes an hour to compile on iOS (plus Android and Huawei versions) and without paying more money everything slowed down, a simple PR would not get the tests to run for a solid hour blocking the entire team.

Github Actions are quite good actually

They are fast, already run on the same platform where the code is, setting them up was a breeze and they are plenty fast

Getting things to run was a breeze, not a fan of yaml, but setting up the first iteration took 5 mins, here is a sample yaml:

name: JS Checks
on: push

jobs:
  tests:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
      - name: Use Node.js 12.x
        uses: actions/setup-node@v2.1.2
        with:
          node-version: 12.x
      - name: Install Dependencies
        run: yarn
      - name: Run tests
        uses: yarn test

However, I wanted to push things a bit further, I hated having to open the bitrise log page, because loading web pages nowadays is sooo slow, so I wanted to see my failing tests directly on my PR!

A quick google search revealed nothing of use

Introducing gh-jester

I forked an old project that claimed to do what I needed, removed the unnecessary parts and added actually the useful output that I was looking for, you can check the source code, here is a finished YAML you can copy and paste into your github repo:

name: JS Checks
on: push

jobs:
  tests:
    runs-on: ubuntu-latest

    steps:
      - name: Cancel Previous Runs
        uses: styfle/cancel-workflow-action@0.6.0
        with:
          access_token: $
      - uses: actions/checkout@v2
      - name: Use Node.js 12.x
        uses: actions/setup-node@v2.1.2
        with:
          node-version: 12.x
      - name: Install Dependencies
        run: yarn
      - name: Run tests
        uses: ospfranco/gh-jester@v1.0.13
        with:
          post-comment: true
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GITHUB_CONTEXT: ${{ toJson(github) }}

Basically, it will run your jest tests and if the tests are failing it will post a nice resume on the commit itself (which will also appear on the PR), bear in mind, the trigger needs to be [push] for it to correctly post the comment with the info.

And that is it! Now all the info for your PR is right on the comment section, enjoy!