Running Cypress Tests With GitHub Actions in Parallel

Created: Sep 03, 2021 – Last Updated: Sep 03, 2021

Tags: Tooling

Here’s a quick explanation and example of how you can run multiple Cypress tests in parallel using GitHub Action’s matrix feature and without the need to use Cypress Cloud.

If you want to see a real-world application using this pattern, you can checkout my gatsby-themes repository (opens in a new tab).

#Prerequisites

Let’s say you use Create React App (CRA) and have a small list of E2E tests that you want to run inside cypress/integration:

cypress/
├─ integration/
│  ├─ homepage.js
│  ├─ contact-form.js
│  ├─ seo.js

In order to run the tests you’ll need to build the CRA app, serve the app (opens in a new tab), and only then start Cypress.

#GitHub Action Workflow

Set up the the workflow file and add the two jobs you need:

.github/workflows/e2e_testing.yml

yaml

name: E2E Testing
on: pull_request
jobs:
  install:
    runs-on: ubuntu-latest
  e2e_tests:
    runs-on: ubuntu-latest
    needs: install
    container: cypress/browsers:node14.17.0-chrome91-ff89

You can adjust the on trigger to your needs and change the container (at the time of writing this it was the latest LTS image).

Add the necessary checkout, Cypress action and build steps to the workflow:

.github/workflows/e2e_testing.yml

yaml

name: E2E Testing
on: pull_request
jobs:
  install:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Install
        uses: cypress-io/github-action@v2
        with:
          runTests: false
      - name: Run CRA Build
        run: yarn build
      - name: Save Cypress artifacts
        uses: actions/upload-artifact@v2
        with:
          name: build
          if-no-files-found: error
          path: build
  e2e_tests:
    runs-on: ubuntu-latest
    needs: install
    container: cypress/browsers:node14.17.0-chrome91-ff89
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Download Cypress artifacts
        uses: actions/download-artifact@v2
        with:
          name: build
          path: build

The cypress-io/github-action@v2 action sets up Cypress, installs dependencies and caches them between runs. In the install step it uses runTests: false since you only want to set up the container, not run tests just yet. With actions/upload-artifact@v2 the output of CRA build is saved for the e2e_tests runs.

In this last step you use the matrix feature (opens in a new tab) to tell cypress-io/github-action@v2 to run each of your tests in parallel. This does not use the parallel option of the action itself but defines the spec through the matrix itself. The entries in the matrix.containers are the names of your files inside cypress/integration.

Here’s the complete workflow file:

.github/workflows/e2e_testing.yml

yaml

name: E2E Testing
on: pull_request
jobs:
  install:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Install
        uses: cypress-io/github-action@v2
        with:
          runTests: false
      - name: Run CRA Build
        run: yarn build
      - name: Save Cypress artifacts
        uses: actions/upload-artifact@v2
        with:
          name: build
          if-no-files-found: error
          path: build
  e2e_tests:
    runs-on: ubuntu-latest
    needs: install
    container: cypress/browsers:node14.17.0-chrome91-ff89
    strategy:
      fail-fast: false
      matrix:
        containers: [homepage, contact-form, seo]
    steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: Download Cypress artifacts
        uses: actions/download-artifact@v2
        with:
          name: build
          path: build
      - name: Cypress Test
        uses: cypress-io/github-action@v2
        with:
          spec: cypress/integration/${{ matrix.containers }}.js
          browser: chrome
          start: yarn start
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

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