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Testing web apps in JavaScript using Puppeteer

This quickstart will show you how to visually test web apps in JavaScript using Puppeteer. Visual testing can help you catch problems that traditional automation struggles to find. You can also leverage Applitools Ultrafast Grid to run your tests across all the major browsers in a fraction of the time as other cross-browser testing platforms.

After preparing your environment, this three-step quickstart should take about 15 minutes to complete.

Need extra help?

If you get stuck on this example, don't suffer in silence! Please reach out to us to get things working. We can also help you get Applitools running in your own project.

Step 1: Preparing your environment​

You'll need a few things to run this quickstart:

  1. An Applitools account, which you can register for free.

  2. A recent version of Node.js.

  3. A good JavaScript editor like Visual Studio Code.

Step 2: Getting your example project​

Downloading the example project​

The example project is located at https://github.com/applitools/example-puppeteer-javascript. Clone this repository to your local machine:

git clone https://github.com/applitools/example-puppeteer-javascript.git
cd example-puppeteer-javascript
Don't have Git?

Instead of running git clone, you can download the project as a ZIP file and extract it.

Installing the dependencies​

The example project uses npm for package management. Run the following command (which work for both example projects on any operating system):

npm install

When this command installs Puppeteer, it will also automatically install Chromium. Puppeteer will run its tests against this Chromium instance.

Adding Applitools to Another Puppeteer Project?

This example project already has the Applitools Eyes SDK as a dependency. If you want to add the Applitools Eyes SDK as a new dependency to another Puppeteer project, run the following command:

npm install --save-dev @applitools/eyes-puppeteer

Deciding how to run tests​

There are two ways to test the visual snapshots captured by the test:

  1. Using Applitools Ultrafast Grid for cross-browser testing in the cloud
  2. Using Applitools Classic runner on your local machine

If you are not sure which one to pick, read Leveraging the Applitools platform. For most cases, we recommend Applitools Ultrafast Grid. The docs for Ultrafast Grid and Classic runner provide more information.

Walking through the code​

The project contains one visual test case, which is located at test/acme-bank.test.js. acme-bank.test.js is a test module that covers login behavior for the ACME Bank demo web app. It uses the Applitools Eyes SDK for Puppeteer to execute the test. The variables at the top control how tests will run:

  • Set USE_ULTRAFAST_GRID to true to use Ultrafast Grid or false to use the Classic runner.

Setup varies slightly for these different options. In-line comments explain every section. Read it top to bottom to understand how it works:

Test setup code is slightly different between Ultrafast Grid and the Classic runner. In-line comments explain every section. Read it top to bottom to understand how it works:


Step 3: Running your tests​

Setting Applitools variables​

Before running the visual test, you must find your Applitools API key and set it as an environment variable named APPLITOOLS_API_KEY. You may set it through your IDE (if applicable), or you may set it from the command line like this:

export APPLITOOLS_API_KEY=<your-api-key>
Having trouble with environment variables?

If you have trouble setting the APPLITOOLS_API_KEY environment variable, you can hard-code your API key like this:

// Change the following line:
// applitoolsApiKey = process.env.APPLITOOLS_API_KEY;
applitoolsApiKey = "<your-api-key>";

However, be warned: hard-coding secrets is poor practice. Do this only temporarily for debugging, and never commit hard-coded secrets to version control.

You may also need to set your Applitools Eyes server. By default, tests will use the public Applitools Eyes server at eyes.applitools.com. However, if your team is using a private Applitools Eyes server, you can target it by setting the APPLITOOLS_SERVER_URL environment variable. (If you are using a free Applitools account, then use the public server.)

Launching visual tests​

To launch the tests, run:

npm test

After your tests run, you should see results in the Eyes Test Manager. You can log into the Test Manager at eyes.applitools.com or at the address for your private Applitools Eyes server.

When you run tests with the Applitools Ultrafast Grid, the tests will run one time on the local machine, and then they will upload snapshots to render on each target configuration in the cloud. The Test Manager will show a separate result for each rendering. When you run tests with the Applitools Classic runner, the Test Manager will show the one snapshot from your local machine.

You can also change the web page to inject visual bugs:

// await page.goto('https://demo.applitools.com');
await page.goto('https://demo.applitools.com/index_v2.html');

If you rerun the tests, then they should yield "unresolved" results for you to review. Visual differences will be highlighted in magenta. It's up to you to accept (👍) or reject (👎) the changes. Applitools will remember your decisions for future analysis.

Need extra help?

Again, it's okay. If you get stuck on this example, don't suffer in silence! Please reach out to us to get things working. We can also help you get Applitools running in your own project.

Taking the next steps with Applitools​

Congratulations on completing this quickstart! There's still so much to learn about visual testing with Applitools, but you're off to a great start.

Resources for next steps:​

  1. 🤖 Learning how visual testing works
  2. ↔️ Setting match levels for visual checkpoints
  3. 💥 Troubleshooting common issues
  4. 🐞 Reporting bugs
  5. 🗺 Detailed overview of visual testing with Applitools

You can also:​