How to Test JavaScript Code Automatically?

Testing JavaScript code automatically can help us to ensure that our code works as intended and catches any bugs or errors it contains. In this article, you will learn about how we can test JavaScript code automatically.

Several types of tests are there which can be performed on JavaScript.

Unit Tests

In this testing we test all the function unit; modules or components which JavaScript program contain. The goal of unit testing is to verify that the smallest possible pieces of code work as expected. In JavaScript, unit testing can be performed using frameworks such as Jest or Mocha.

Integration Testing

In this testing methodology we test how different parts of the JavaScript code work when it is combined together. The goal of integration testing is to verify that the all the different components of the program work as expected when combined with other component. In JavaScript, integration testing can be performed using frameworks such as Cypress and Selenium.

End-to-end Testing

This testing method is used to test the entire flow of the application. Using this teasing we check from the user interface to the backend and verify it’s working. The goal of end-to-end testing is to verify that the application works as expected from the user's perspective. In JavaScript, end-to-end tests can be performed using frameworks such as Protractor or TestCafe.

Performance Testing

In this testing we check JavaScript code using various parameters and conditions like heavy load and high traffic of user and verify its working under all these conditions. The goal of performance testing is to identify bottlenecks and improve the performance of the application. In JavaScript, performance testing can be performed using tools such as Apache JMeter or LoadRunner.

Security Testing

This teasing is used to identify code which contain vulnerabilities as it can lead to exploited by attackers. The goal of security testing is to ensure that the application is secure and does not expose sensitive data to unauthorized users. In JavaScript, security testing can be performed using tools such as OWASP ZAP or Burp Suite.

Testing JavaScript Code Automatically

Unit Testing With Jest

We use Jest (JavaScript Code Runner) to create, structure and run the test cases for functional component. The goal of unit testing is to verify that the smallest possible pieces of code work as expected. Using Jest, we can test the individual component and verify if our input is generating desired output. For running the test cases with Jest we will have to install it using NPM (Node Package Manager). After the installation of Jest, we create a file to test our code. This test file contains set of test cases which is used to call the individual functions and components using different-different test cases and verify if it is giving expected output. We can run the test cases using command line interface of Jest or using Webpack, Gulp build tool.

Integration Testing With Cypress

Cypress is a JavaScript end-to-end testing framework that is used for integration testing. Integration testing involves testing of all the different components of the program and verify if it works as expected. Cypress provides a suite of tools to simulate user interactions and test your code's functionality end-to-end.

To use Cypress, we install it using NPM, and create a test file that defines your test scenarios. Cypress provides a web-based test runner that allows you to interact with your code as a user would. You can then use Cypress's APIs to simulate different user interactions and assert that the output is as expected.

Automated Browser Testing with Selenium

This is a popular testing tool which is used to automate in any preferred programming language. This allows us to automate the testing of our JavaScript code in a real browser environment.

To use Selenium, we install it using NPM, and same as unit testing, we create a file to test our code. This test file contains set of test cases which is used to call the individual functions. Selenium provides APIs that allow us to automate browser interactions, such as clicking buttons or filling out forms. You can then use assertions to ensure that the output is as expected.

We can also test JavaScript code online using some online editor platforms.

Conclusion

Automated testing is an essential part of any software development process. By automating your JavaScript tests, you can catch bugs early and ensure that your code works as intended. Whether you choose to use Jest for unit testing, Cypress for integration testing, or Selenium for automated browser testing, make sure to write comprehensive test cases to cover all possible scenarios in your code.