Selenium: Definition, How it works and Why you need it

Types of testing that are commonly automated with Selenium are:

Compatibility Testing:

Done by QA professionals/Testers to ensure that the web app meets performance benchmarks on different browser-OS combinations. For example, testing on different devices (mobile and desktop) to ensure that the front-end fits to scale (responsive); testing on different browsers to see if video ads render on the pages as they should.

Performance Testing:

Series of tests done by QA professionals/Testers to ensure that the project meets performance benchmarks set by the stakeholders. Tester writes a script that checks whether all elements on homepage load within 2 seconds on different browsers/browser versions.

Integration Testing:

Done by developers to verify that units/modules coded separately (that work on their own), also work when put together. Parallel Test Calculator, for instance, has separate layers. UI takes input and business logic calculates the output—then sends it back to UI to display. The tester could verify whether they are able to relay data/output when integrated.

System Testing:

aka Black Box testing. Done by Testers/QA professionals with no context of the code or any previously executed tests. Typically centered on a single user workflow. The check-out process on a product website, for instance, comprises of: validating user credentials, fetching products from the cart, checking their availability, and validating payment details—before redirecting to the bank website. The tester could write a script to verify that the entire system is functional.

End-to-end Testing:

Also done by Testers/QA professionals, typically from the user’s point of view. The aim is to verify that all touchpoints on the web app are functional. From the previous example, the tester could write a series of test cases to check that sign-up, product search, checkout, review, bookmark, and all other features function as intended (and fail when invalid values are entered in input fields).

Regression Testing:

A series of tests done to ensure that newly built features work with the existing system. From the same example, say the product website launches a new feature (promotional codes) that automatically apply to eligible items before checkout. The tester could write cases to verify that it doesn’t break the rest of the checkout feature.

Well-written test suites can also automate Smoke and Sanity testing with Selenium.