#automated #testing #selenium #grid #docker #framework #tool

#selenium_grid_with_docker_series

Selenium Grid allows the execution of WebDriver scripts on remote machines by routing commands sent by the client to remote browser instances.

Grid aims to:

Provide an easy way to run tests in parallel on multiple machines

Allow testing on different browser versions

Enable cross platform testing

Hub is a central point or a local machine that receives all the test requests and distributes them to the right nodes. The machine which actually triggers the test case known as Hub.

There can be only one hub in a selenium grid.

The machine which is containing the hub triggers the test case, but you will see the browser being automated on node machines.

Nodes are the Selenium instances which will execute the test cases that you loaded on the Hub. Nodes can be launched on multiple machines with different platforms and browsers.

With standalone mode in Grid, setting up both hub and nodes on the same local machine is absolutely feasible and it is working seamlessly.

When would you use a Selenium Grid?

To run your tests in parallel, against different browser types, browser versions, operating systems

To reduce the time needed to execute a test suite

Selenium Grid runs test suites in parallel against multiple machines (called Nodes). For large and long-running test suites, this can save minutes, hours, or perhaps days. This shortens the turnaround time for test results as your application under test (AUT) changes.

Grid can run tests (in parallel) against multiple different browsers, and it can run against multiple instances of the same browser. As an example, let’s imagine a Grid with six Nodes. The first machine has Firefox’s latest version, the second has Firefox “latest minus one”, the third gets the latest Chrome, and the remaining three machines are Mac Minis, which allows for three tests to run in parallel on the latest version of Safari.

Execution time can be expressed as a simple formula:

Number of Tests * Average Test Time / Number of Nodes = Total Execution Time

(selenium.dev)

Docker is a software platform that allows you to build, test, and deploy applications quickly. Docker packages software into standardized units called "containers" that have everything the software needs to run including libraries, system tools, code, and runtime. Using Docker, you can quickly deploy and scale applications into any environment and know your code will run.

The purpose of this is to introduce Docker, so I will not go into the architecture of Docker 😁.

Fast, consistent delivery of your applications: Docker streamlines the development lifecycle by allowing developers to work in standardized environments using local containers which provide your applications and services. Containers are great for continuous integration and continuous delivery (CI/CD) workflows.

Responsive deployment and scaling: Docker’s container-based platform allows for highly portable workloads. Docker containers can run on a developer’s local laptop, on physical or virtual machines in a data center, on cloud providers, or in a mixture of environments.

Running more workloads on the same hardware: Docker is lightweight and fast. It provides a viable, cost-effective alternative to hypervisor-based virtual machines, so you can use more of your server capacity to achieve your business goals.

What do we usually do to config Selenium Grid:

Download jar file and run on separate machines

Host hub and register every single node to hub

Set up required dependencies to run for each machines

Manage browser version (drivers)

This is costly and sometimes a time-consuming task for the testers. However, Docker helps us to solve cost-related and time-consuming problems by:

Dependencies are bundled inside specific Selenium Docker image

Share system resources so it's more lightweight than using virtual machines

Easily to manage all version complexity with docker registry against multiple browsers and versions

Capability to scale up

In this series of Selenium Grid with Docker, I will provide you instructions on how we set up:

Part 1 - Set up Selenium Grid with different modes

Part 2 - Set up Selenium Grid with Docker in standalone and hub-node on different machines

Part 3 - Set up Selenium Grid with Docker compose

Stay tuned for coming posts in this series.