Each programming language used to automate testing has its own characteristics. JavaScript is no exception. Dzmitry Prakapuk, Software Testing Team Leader, explained why JavaScript is so popular with test automation engineers, what the features of the language are and what the advantages of its tools are.
What shall a test automation engineer need to know about JavaScript?
- JavaScript is a dynamically typed language. In dynamic typing, you can omit the definition of data types for variables, it is performed automatically during program execution unlike static typing when data types for variables must be defined before the program is executed. With dynamic typing, the code is faster to write, but in the future, you can skip errors.
- JavaScript is a multi-paradigm language: it supports both functional and object-oriented programming styles. As part of automated testing, multi-paradigm of JavaScript gives flexibility in building the project architecture, the ability to write tests easily and quickly.
- JavaScript has the largest package infrastructure for the language. For example, if you need to work with PDF, XLS, or other files as part of tests, JavaScript already has a package that will help you test any file format.
Advantages of JavaScript Automation Tools
No Selenium WebDriver initialization
Selenium WebDriver is a tool for automating web browser actions. To work with Selenium WebDriver, it needs to be initialized, that is to declare. However, you need to declare it correctly. Different approaches are used in the form of design patterns.
In JavaScript tools, we do not need to initialize Selenium WebDriver and choose which approach to use. The developers of the tools took into account the previous experience and implemented initialization of the driver for us. In other languages, we need to declare Selenium WebDriver ourselves. First, it takes time. And secondly, it can be hard for a beginner automation engineer to do it correctly.
Wide choice
This is especially well seen in the example of UI automation, where 3 approaches of JavaScript tools are used:
- Selenium based. A classic approach for automating web applications when we communicate with the browser (Chrome, Firefox) via Selenium WebDriver.
- DevTools Protocol based. This is a new approach in which we communicate with the browser not via Selenium WebDriver, but via DevTool.
- JavaScript based. In this approach, we communicate with the browser via JavaScript-implemented functionality.
Technical capabilities
Automation does not stand still. And with the development of frontend technologies in testing, it became necessary to work with the browser's Network Tab to perform high-quality checks of the application's performance. In JavaScript, it is possible to work with the browser's Network Tab without connecting additional libraries (this is the time to search, study the connection), which is not available in Java, C#, Python tools.
Low entry requirements
To start writing autotests in JavaScript, it is enough:
- To be able to search for locators. A locator is a string that allows you to find an element (button, input field) on a page of a web application or website.
- To know the basics of JavaScript. This includes data types, conditional expressions, working with functions, arrays, and loops.
• To know Page Object. Page Object is a basic approach for organizing an automation project (test framework).
JavaScript is the frontend language
Therefore, if you have a web project, then the developers will definitely know JavaScript and will help organize the infrastructure of the test framework, make a review, write tests.
Infrastructure for development
The JavaScript environment is the fastest growing of all. Therefore, with a high degree of probability, when performing tasks, you will be able to find and use a ready-made package. There are already more than 1.3 million of them in the JavaScript environment.
Where are JavaScript tools used?
- In automation of web applications. Basically, these are emulations of user actions in the browser. For example, you can automatically test the application login form and other more complex cases.
- In automation of services. All applications have services that implement the basic logic of the application, and JavaScript tools make it possible to start automating services quickly.
- In automation of desktop applications written using Electron technology. The most famous applications written in Electron are Skype and Visual Studio Code. JavaScript has tools to test the visual part and the application itself.
- In automation of mobile applications. More and more mobile applications will be developed, so mobile automation is one of the trends. With JavaScript tools, you can automate both Android and iOS applications.
Do you want to study one of the top four programming languages and learn how to create test frameworks, thanks to which the product gets to end users earlier? Then register for free training on automated software testing from EPAM!
