Selenium is one of the best tools to perform web browser automation testing. It is an open-source toolkit that provides many ways to automate various applications.
But even though Selenium supports many functions, it is not advisable to be used for application programming interface or Selenium API testing.
Continue reading this article to learn more.
What is API testing, anyway?
Before diving into Selenium testing, you must first know what APIs are.
API stands for application programming interface—a computing interface used for interaction between different applications.
For example, let us say you want to build an app for iOS and Android devices. You can use the same code base for both apps and still be able to customize the features of your app.
With an API, you can access the required functions from your web application project.
Likewise, APIs allow applications in different environments to communicate with each other.
REST API testing
REST API automation testing is a process where requests verify the functionality of a system that uses REST.
What is REST?
Representational State Transfer (REST) is an architectural style for developing websites. It was created by Roy Fielding, one of the authors of the HTTP specification.
It provides a consistent way for external applications to interact with your service. Besides that, it is independent of the installation of the service itself. You can also use it to define helpful communication inside your system.
Here are the two most common ways to test a web service’s functionality through REST APIs:
- Manual testing: Where you might use any other kind of application for this purpose.
- API automation testing: Uses scripts and programs to access resources on an active server.
The core idea behind REST is that all resources are identifiable through a single URL. Likewise, they are only using built-in operations.
HTTP responses and status codes for testing RESTful APIs
You can do REST API testing in four ways, including:
- PUT – It creates a new resource or updates an existing resource with the requested payload. Put request changes in data at a URL.
- GET – When the app starts, it performs an API GET request to get a list of contacts to show in the app. You may complete the GET method and status code using Unirest.
- POST – Using REST API, you can complete an HTTP POST request. Then, add a basic JSON library to your classpath so you may construct JSON or XML objects in your code. Besides that, you can create a new entity with it.
- DELETE – An HTTPS delete request deletes a resource from the server defined by the provided URL.
Requirements for REST API test
- Java Setup
- IDE Setup
- Maven Setup
- Create a maven project
- Add Rest Assured Dependencies
- Setup Maven Compiler Plugin
- Create a user for the automated tests
Can you integrate Rest API automation testing with Selenium Webdriver?
The Selenium interface is an example of an API, and it lets you test functionality in the browser.
Selenium is a powerful tool for testing web applications. Using the Selenium framework, you can complete a variety of tasks, such as:
- Automatically log into websites and submit forms
- Go to different pages and check the presence of expected elements
- Upload or download files from websites
- Use other browsers (Firefox, Chrome, IE, etc.) with the same test data formats
- Run tests on remote machines (e.g., mobile phones) that don’t have their screens or keyboards
Using Selenium, your test simulates user interaction with a browser. It makes it an ideal tool for functional or end-to-end testing.
But beyond functional or end-to-end tests, Selenium has its limitations in API testing.
The primary purpose of Selenium is to automate the browser, so you cannot write and execute unit tests using it. It also does not support database testing.
If you need to test your APIs that are not web-based, this tool is not the best choice.
Here are the reasons why you should not use Selenium to execute performance test:
- It limits your ability to render trivial loads.
- Selenium does not offer a mechanism for measuring response times, and it lacks an efficient way of gathering and presenting data.
- It is not easy to understand the performance characteristics.
- Selenium does not work with Windows’ dialogs, like file upload/download screen.
So, Selenium is only helpful for testing a web application, not for REST API testing. If you need to test an API, you should search for another tool or Java library.
Takeaways
If you’re looking for ways to automate your work, Selenium is one tool that can help you with browser automation and user interface test automation.
But if you’re looking to automate your API testing, Selenium might not be the right choice. API testing requires different automation frameworks and tools.
