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How to Automate API Test Cases Using Rest Assured?

By February 4, 2021August 23rd, 2023No Comments6 min read
How to Automate API Test Cases Using Rest Assured?

Trends in technology have been rapidly changing, bringing out the better and still having room for improvement. With a similar aim of providing better software, APIs play an essential role. APIs are now core business logic for software and have a while API level dedicated, thus making API testing a necessity. Over a period of time, many software and tools are being developed, introduced, and used for better testing of APIs and to automate the testing process. These tools provide you with a list of features and make it easy to set up the required environment and test the APIs. Today our Rest Assured Tutorial covers various basic points, How to Automate API Test Cases Using Rest Assured and that will help you to learn about rest API testing.

From Our rest assured API testing tutorial, you will learn:-

  • API Testing and How is it automated?
  • What is Rest Assured Testing?
  • Why Rest Assured is used?
  • How Does Rest Assured work?

How to Automate API Testing?

Testing is a crucial stage of the software development life cycle and now APIs being the core of any software, it makes it more than important to test these APIs with proper setup and tools. API unlike any other aspect of the software is GUI-less yet its impact is witnessed all over the software. Testing APIs ensures the smooth functioning of business-level logic and it requires doing so with various perspectives with a number of test cases. 

This is where Automation jumps in and assists in testing multiple APIs in a cycle. Scripts and Test cases are written once to be used multiple times. There are many reasons why it is recommended to write an automated test for the API level, but the best reason would be the increased speed of execution these tests give you compared to that of GUI-based testing, along with the broader scope. 

Now that we know what API testing is and its importance, let us move to the focus point which is REST Assured.

Learn also: How to Use Postman to Test API?

What is Rest Assured Testing?

As mentioned earlier, a number of tools are used in testing, and REST Assured is just another but one of the most popular Java libraries that are used to write and monitor tests for the RESTful Web Services. A number of open-source and commercial tools are available for the same purpose.    

Simply speaking, Rest Assured is ready to use Java APIs used for testing the Restful web service and validating the same. Web Services based on XML and JSON can be tested using REST Assured and it supports the POST, GET, DELETE, and all major requests. It is also used to validate the response received. Based on the Groovy, Rest Assured implements the builder pattern to create the requests, set heads, analyze the received response and finally match that with expected data.   

Along with supporting all HTTP methods, it also supports requests that include OAuth and OAuth 2.0.

Why Rest Assured is used?

Every tool for whatever purpose it is made for, has its advantages and disadvantages and out of all the benefits that REST assured assures you, these are highlights: 

  • Open Source, Java Based, and supports both XML & JSON format.
  • With the support of Given/When/Then notation, it makes your test more readable to humans. 
  • For the basic step like the HTTP method, sending a request, and receiving & analyzing the response, no extra or separate code is to be written. 
  • Being the Java Library, REST assured can be easily integrated with CI/CD, also with frameworks like JUnit. 

Now that we know what REST assured is and why it is preferred, let us understand how it works. 

Read Also: How to Perform API Testing?

How Does Rest Assure Work?

There are two basic ways to make it happen, either using an IDE or along with Command Prompt, but the IDE way is preferred and easy to work with as it has an added advantage of IDE features. Both ways are quite similar and intend to deliver a likely result. To break it down in simple words, there are three steps within which the whole process of automating with REST assured can be summoned up. 

First, you create a request with all details headers and parameters. Once the request is created, send the request through the HTTP method as usual. Lastly, check the response received. This is the basics of how Rest Assured works.  

Now that we know what are the basic steps, let us look into the working of REST assured with an IDE. IDEs like Eclipse, TestNG, or Maven are used. If you are using any of such IDE, make sure the JAVA_HOME path is correctly set, along with JDK & JRE paths. For Eclipse, go on to create a new Maven Project. Relevant dependencies for REST Assured, testing, etc are a must. A sample of the pom.xml file can be found on the Internet and make sure all the required jar files are added. Jenkins software is to be installed and once done you can go to http://localhost:9090/, create a user, and log in. 

Moving on, setting up IDE is a basic part of the process, the main task is to write the test script that satisfies our requirements. REST Assured is Java-based, so you will be scripting in Java. 

Creating a Test Automation Script begins with creating a Testing Class and a new XML file. Alternatively, you can simply create a new Java Class instead of testing one and later convert it, but it is recommended to have a testing class. Your first Java class uses HTTP methods like getting, PUT, etc, and the XML file created earlier will execute this class. Upon execution, Method we called in the class file will be requested and the response received will be printed, ending the test with a tally of tests run. failed and skipped.

A simple example would be to search a simple term on a base URL. This starts with mentioning a base URL and base Path, then adding the search term and required parameters. Upon sending the request, the URL will be created and a response will be received. The response will be in JSON format and further validations like verifying HTTP response, relevant search term, the duplicity of the result, etc. Automated test scripts will be written to do this single task multiple times.  

A major reason why test cases or scripts are written and widely used is the time is saved along with properly implementing a cycle of repeated tasks. 

TO Wrap It Up

According to Top Web API Testing Companies, API itself being an essential part of the software, makes API testing a crucial step, and thus a number of methods and tools are present. REST Assured is an open-source, Java-based library to test REST web services. REST assured does not have a GUI and supports XML & JSON. REST Assured works in three simple steps and automated test scripts are written. A Java class consists of the HTTP method while an XML file is responsible for executing the Java class. 

We hope our rest API automation testing tutorial helps you to explore How to Automate API Test Cases Using Rest Assured.

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