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Testing web apps in Python using Selenium WebDriver

This quickstart will show you how to visually test web apps in Python using Selenium WebDriver and pytest. Visual testing can help you catch problems that traditional automation struggles to find.

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 Python 3.

  3. A good Python editor like Visual Studio Code or JetBrains PyCharm.

  4. An up-to-date version of Google Chrome.

  5. A corresponding version of ChromeDriver.

    Installing ChromeDriver
    The major version numbers of Chrome and ChromeDriver must be the same. Otherwise, Selenium WebDriver may raise an exception when it is initialized. For example, Chrome v101 requires ChromeDriver v101. ChromeDriver must be installed into a directory covered by the system PATH variable. Follow the instructions on Selenium's Install browser drivers page. On macOS and Linux, the recommended location for the chromedriver executable is the /usr/local/bin directory. You can test that ChromeDriver is working by running the chromedriver -v command to print its version.

Step 2: Getting your example project​

Downloading the example project​

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

git clone https://github.com/applitools/example-selenium-python-pytest.git
cd example-selenium-python-pytest
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 pip for package management. Run the following command (which works on any operating system):

pip3 install -r requirements.txt
Adding Applitools to Another Python Project?

This example project already declares the Applitools Eyes SDK as a dependency. If you want to add the Applitools Eyes SDK into an existing Python environment, run the following commands:

pip3 install eyes-selenium

Deciding how to run tests​

The test uses Selenium WebDriver to automate the browser. There are two places to run your Selenium WebDriver session:

  1. On your local machine (which is the default option)
  2. On Applitools Execution Cloud

If you run WebDriver locally, then you need to set it up and manage it yourself. If you use Execution Cloud, then Applitools will manage WebDriver for you. It will also automatically heal broken locators and wait for elements to be ready. If you would like to try Execution Cloud, please request access. The docs for Execution Cloud provide more information.

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

Walking through the code​

All test setup and cleanup is handled by a set of pytest fixtures located at tests/conftest.py. 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.
  • Set USE_EXECUTION_CLOUD to True to use Execution Cloud or False to run WebDriver sessions locally.

Setup varies slightly for these different options.


The project contains one visual test case, which is located at tests/test_acme_bank.py. test_acme_bank is a pytest test module that covers login behavior for the ACME Bank demo web app. to execute the test across multiple browsers in Applitools Ultrafast Grid. With the Ultrafast Grid, you can specify different browser types, viewport sizes, and even mobile devices.


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 in the 'api_key' fixture:
# return os.getenv('APPLITOOLS_API_KEY')
return "<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​

Run the following command to launch tests:

python3 -m pytest -s -v tests

To run tests headlessly, set the HEADLESS environment variable to true.

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:

# webdriver.get("https://demo.applitools.com")
webdriver.get("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. Setting match levels for visual checkpoints
  2. Organizing Tests Into Batches
  3. Run A/B Tests

You can also:​