Percy on GitHub actions

percy.yml

# This goes into .github/workflows/percy.yml
name: Visual Regression Tests

on:
  push:
    branches:
      - master
  pull_request:

jobs:
  build:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        node-version: [12.x]

    steps:
      - uses: actions/checkout@v1
      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v1
        with:
          node-version: ${{ matrix.node-version }}
      - uses: actions/cache@v1
        with:
          path: ~/.cache/yarn
          key: ${{ runner.os }}-yarn-${{ hashFiles(format('{0}{1}', github.workspace, '/yarn.lock')) }}
          restore-keys: |
            ${{ runner.os }}-yarn-
      - name: install
        run: yarn
      - name: build
        run: yarn build
        env:
          CI: true
          VRT: true
          PRODUCTION: true
      - name: test
        run: yarn test:visuals
        env:
          CI: true
          PERCY_TOKEN: ${{ secrets.PERCY_TOKEN }}
          PERCY_COMMIT: ${{ github.sha }}
          # github.head_ref is only defined on pull requests
          # When the type is not a PR it must be a push. We can then read
          # the ref from github.event.ref, which most likely contains "refs/heads/master"
          # So we would have PERCY_BRANCH: ${{ github.head_ref || github.event.ref }}
          # But Percy expects just the string "master" without the /ref/heads prefix.
          # That's why it has to be hardcoded. This is okay, since regular pushes are
          # only happening on master and everything else must be a PR.
          PERCY_BRANCH: ${{ github.head_ref || 'master' }}
          PERCY_PULL_REQUEST: ${{ github.event.number }}