How to make Selenium testing more efficient with Docker

The reliability and compatibility of web applications across different environments are crucial. Docker, a popular containerization platform, offers a streamlined way to achieve this by providing a consistent testing environment.

In 2022, Docker accounted for 27 percent market share of the containerization technologies market. – Statista

What is Docker?

Docker is an open-source platform that automates the deployment of applications in lightweight portable containers. These containers package applications and their dependencies together, ensuring consistency across different environments.

Why to use Docker for Selenium testing

• Isolation: Each test runs in a separate container, preventing interference between tests.
• Consistency: The testing environment is consistent across different machines and environments.
• Efficiency: Tests can be parallelized easily using Docker, reducing execution time.
• Scalability: Docker allows you to scale up your testing infrastructure effortlessly.

Using Docker for application compatibility

You need to ensure that your application is compatible with different browsers (e.g., Chrome, Firefox) and different versions of those browsers. Additionally, as your application’s functionality grows, multiple tests need to be run concurrently to maintain efficiency.

Benefits of leveraging Docker

• Regression testing: It is a process of testing your application to ensure that it still works correctly after changes have been made to it. By using Docker, you can create a consistent environment for regression testing, which can help you identify and fix bugs more quickly.
• Parallel test execution: Docker can help you run multiple tests in parallel, which can significantly reduce the time it takes to execute all your tests. This is especially beneficial for large test suites that can take a long time to execute.
• Consistent environment: Docker creates isolated environments for each test, which ensures that each test runs in a clean environment that is free of any dependencies or configurations from other tests. This can help prevent test failures caused by environmental factors.
• Scalability: You can easily add or remove containers as needed. This can be helpful if you need to increase the number of tests that you are running or if you need to test on many browsers or devices.
• Reduced test execution time: Docker can help reduce the time it takes to execute tests by sharing resources between containers and caching dependencies. This can be a significant benefit for large test suites that can take a long time to execute.

Setting up your environment with Docker

– Installing Docker

To get started, install Docker on your machine by following the instructions on the official Docker website (https://www.Docker.com/).

– Creating a Selenium Test Suite

Develop a Selenium test suite using your preferred programming language (Java, Python, etc.) and testing framework (JUnit, TestNG, etc.). Ensure your tests are organized and ready for execution.

-Configure Docker Compose file

Docker Compose is a tool for defining and running multi-container Docker applications. Create a Docker Compose YML file to configure your container and any other services like Selenium Grid and web browsers like Firefox, Chrome, etc.

– Example of Docker-compose.yml

version: “3”
services:
Chrome:
image: selenium/node-chrome:latest
shm_size: 2gb
depends_on:
– selenium-hub
environment:
– SE_EVENT_BUS_HOST=selenium-hub
– SE_EVENT_BUS_PUBLISH_PORT=4442
– SE_EVENT_BUS_SUBSCRIBE_PORT=4443

Firefox:
image: selenium/node-firefox:latest
shm_size: 2gb
depends_on:
– selenium-hub
environment:
– SE_EVENT_BUS_HOST=selenium-hub
– SE_EVENT_BUS_PUBLISH_PORT=4442
– SE_EVENT_BUS_SUBSCRIBE_PORT=4443

Selenium-hub:
image: selenium/hub:latest
container_name: selenium-hub
ports:
– “4442:4442”
– “4443:4443”
– “4444:4444”

You can expand upon this file to include more browser nodes or additional services as needed. Each browser node service should link to the Selenium-hub service to establish communication.

Navigate to the directory containing the compose file and run the “Docker compose -f Docker-compose.yml up” command.

This will start the Selenium hub and the specified browser nodes. You can then configure your Selenium test suite to connect to the Selenium hub at the specified URL http://localhost:4444 and distribute the tests among the available browser nodes.

– Configure Selenium code for execution in the remote web driver

DesiredCapabilities chromeCapabilities = DesiredCapabilities.chrome();
// Set any desired capabilities here
URL hubUrl = new URL("http://<selenium-hub ip>:4444/wd/hub"); // URL of the Selenium Grid prepared in container.
If you have set up Docker in local, then the Selenium hub URL will be http://localhost:4444.
WebDriver driver = new RemoteWebDriver(hubUrl, chromeCapabilities );

– Execute the test

When you run your tests, Selenium will route the commands to the appropriate browser node based on the desired capabilities. The tests will be executed in Docker containers.

Offer better quality software products with QA automation

Docker provides an effective solution for executing Selenium tests in a controlled and reproducible environment. By containerizing your tests, you can achieve consistency, efficiency, and scalability in your testing processes. Ensure the quality of your web applications by integrating Docker into your testing workflow.

Softweb Solutions is one of the leading providers of QA automation services. We automate testing processes to improve quality, efficiency, and scalability for businesses of all sizes. We have a team of experienced QA engineers who are experts in Docker and Selenium. We can help you set up a Docker-based Selenium environment and automate your tests. We also offer training and support to help you get the most out of Docker for Selenium testing.

Co-author: Anshita Solanki