Introduction to Selenium Grids

h2k infosysFebruary 10, 2023

0 273 3 minutes read

The state of technology right now is one of fast change. Numerous new pieces of software are being released, and many older pieces are continually updated. The browsers that we use are likewise constantly evolving.

Validating the application with various browser combinations as well as several iterations of the same browser is crucial for a better user experience. Yes, we can install the browsers on our computer, but this has its limitations because each browser flavour can only be installed once at a time. Additionally, managing multiple instances of the same browser on a single workstation is not recommended.

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The Problem

What do you do if you want to run your tests across many OS systems and browsers but you can’t justify employing a third-party solution like Sauce Labs or Browser Stack?

The Solution

You may establish a network of interconnected test machines using Selenium Grid (also called nodes). You can run your tests on various connected nodes using the Hub that controls this network of test computers. Every node functions essentially as a computer (or virtual machine) with an OS and several browsers. This enables us to set up a network of test computers with various Operating systems and browser configurations. You may run tests on a range of Operating Systems and Browser combinations with Selenium Grid.

What is a Selenium Grid?

A testing tool called the Selenium Grid enables us to run our tests on several computers using various browsers. It is a component of the Selenium Suite, which specialises in executing several tests on various machines, operating systems, and browsers. With Selenium Remote, you can connect to it by choosing the desired operating system, browser, and version. These values are specified using Selenium Remote’s capabilities. The three Selenium Grids ideas will be completely explained in a good online Selenium certification course.

A hub and nodes are the two essential components of the Selenium Grid.

What is a Hub?

The hub in Selenium Grid is a machine that serves as the focal point and is where our tests are loaded. Because Hub also functions as a server, it serves as the main control point for the network of Test devices. The Selenium Grid has a single hub, which controls the entire network. When the Hub receives a test with specified DesiredCapabilities, the Hub looks for a node that fits the specified configuration. Saying that you wish to perform the test on Windows 10 and the Chrome browser version XXX is an example. In order to conduct the test on a machine that meets the criteria, Hub will search the Grid for that machine. When there is no match, the hub returns an error. There should be only one hub in a Grid.

What is a Node?

In Selenium Grid, a test machine that chooses to connect with the hub is referred to as a node. Hub will conduct testing on this test machine. A Grid network may contain several nodes. A node should have a variety of platforms, including browsers and OS systems. The node does not require the same operating system as the hub to function.

How does it work?

You must first establish a hub. After that, you can “register” or connect nodes to that hub. Your tests will be executed on nodes, and the hub is in charge of ensuring that they are executed on the appropriate node (e.g., the machine with the operating system and browser you specified in your test).

Why is the Selenium Grid used?

By using Selenium Grid, you can build a straightforward infrastructure of several browsers running on various operating systems, which will provide you with a variety of browsers to deal with in addition to helping you disperse the test load.

There are numerous uses for the Selenium Grid. Here are a few:

When we wish to perform our tests on various browsers, including various browser versions and browsers using various operating systems.
By executing tests concurrently, it is also utilised to shorten the amount of time the test suite needs to finish a test pass.

What is the difference between Grid 1 and Grid 2?

The older Grid 1 and the more recent Grid 2 are the two variants of the Selenium Grid.

While Grid 2 is included with the Selenium Server jar file, Grid 1 has a remote control that is distinct from the Selenium RC server.
While Grid 2 can support both Selenium RC and WebDriver scripts, Grid 1 can only support Selenium RC commands.
Before using Grid 1, we must first install and configure Apache Ant; however, with Grid 2, we do not need to do so.
In Grid 1, each remote control can only automate one browser, however, in Grid 2, each remote control can automate up to five browsers.