How can I run Selenium tests in parallel using Docker?

How can I run Selenium tests in parallel using Docker?

You can run Selenium tests in parallel using Docker by creating a Docker Compose file that defines multiple Selenium containers.

What does the Docker Compose file look like for this setup?

Here's a basic example:

version: '3'
services:
  selenium-hub:
    image: selenium/hub
    ports:
      - '4444'
  chrome:
    image: selenium/node-chrome
    depends_on:
      - selenium-hub
    environment:
      - HUB_HOST=selenium-hub
  firefox:
    image: selenium/node-firefox
    depends_on:
      - selenium-hub
    environment:
      - HUB_HOST=selenium-hub

How do I execute my tests once the containers are up?

You can execute your tests by connecting to the Selenium Hub at http://localhost:4444 and running your test scripts against it.

Can I scale the number of browser instances?

Yes, you can scale the number of browser instances by adding more services in your Docker Compose file or using the --scale option.