How To Automate Code for APIs

APIs are indispensable to digital business ecosystems, as they allow seamless integration of programs and databases with different industry applications, enabling process automation. Research indicates that 98% of businesses currently use public or private APIs and employ more than 900 applications.

To actively meet market demands, developers should be able to test these web APIs quickly and efficiently. This speeds up the development life cycle and ensures good functionality and innovation.

API tests can be written in various programming languages, such as JSON, XML, and Javascript. These languages are more structured and help with easier verification. 

What Is REST API Testing?

This open-source testing technique for web automation tests RESTful APIs for web applications. These APIs can be tested by sending HTTP/S requests to determine whether the REST API works well. These APIs can be rested with different methods such as POST, PUT, GET, and DELETE. 

Benefits of Automating API Testing

Generally, software testing ensures that a piece of software meets quality standards. API automation testing ensures that the APIs function well, whether you are building them for a single application or using them for several services. Automated API testing helps you ascertain that the different endpoints in your API are functioning and enables you to catch bugs.

Moreover, you will be able to add new features by running test cases to detect that everything is intact. Here are some other benefits of automating the code for APIs:

• API testing is generally black-box testing, so the functionality is tested without looking into the internal structure. All you do is provide input and validate the responses. A plethora of datasets can be used in the same test scenario, and they are instrumental in enhancing API test coverage. This is referred to as API automation testing using a data-driven approach. 

• API testing involves the exchange of data in different formats, such as XML and JSON, so it is language-agnostic. This implies that any programming language can be employed for testing APIs. As most languages have libraries to correlate data in these formats, API responses can be validated easily.

• API tests can be carried out during the initial stages of the software development lifecycle. Following an automation approach, you can use mock techniques to verify API and its respective integration. Therefore, you can test the business logic before the graphical user interface (GUI) is developed, thereby saving time and resources.

• Automating API code can help perform more tests in less time. Releases can happen much faster, and when an API fails the test, you can quickly diagnose the problem by finding out the source of the failure. 

• You can set up automated testing in advance to diagnose the edge cases. This helps prevent bugs from moving into the production phase.

• Lastly, automating API code is less costly than making manual efforts. This is because not only is the quantity of work reduced but also the number of hours the staff has to input.

Choosing API Testing Tools

There are several API testing tools available in the market; however, you should ask the following questions to ensure that you make the right choice:

• Does the platform support all types of HTTP requests?

• Can my team learn the software quickly?

• Can the tool integrate with the CI systems my team uses?

• Is the tool able to connect to communication platforms used by my enterprise, such as Slack and Jira?

• Can I extract easy-to-interpret reports from the tool?

Here are some of the commonly used tools for API testing:

DreamFactory

DreamFactory is a robust integration platform that can help you chain multiple APIs to build comprehensive test suites. It helps your organization save time and improve the workflow by automating API testing.

Postman

If you are looking forward to streamlining all the phases of the API development lifecycle, then Postman is a good platform. You can use it for Mac, Windows, and Linux, enabling you to build HTTP requests that can be sent to the server that runs the API. 

Postman offers a user-friendly REST client and a rich interface that can be employed for automated testing. To test your APIs with different data points, you can employ data files. 

Swagger

If you want to design, build, and document REST APIs, you should use this open-source platform. It focuses on creating stable and reusable APIs while following an enterprise’s guidelines and best practices.

Rest Assured

Rest Assured helps you test REST APIs by employing java libraries. It has valuable matching techniques that enable you to verify the expected results. This platform integrates well with Maven, a build automation solution mainly used for javascripts.  Rest Assured has different methods to fetch data from the request, even with complex JSON structures.

Automating API Code

API testing is crucial for the success of your enterprise. The DevOps and QA use it extensively for testing practices. Automated API testing is used widely in the software development process. Automating the API code makes it easy to conduct integration and regression testing whenever changes are made to the application. Moreover, it decreases not only the execution time for the software development cycle but also feedback and redeployments. So, automated API testing improves the overall quality of the application.

As mentioned earlier, API testing is referred to as black-box testing. So, you basically interact with a function without getting to know what’s going on inside. It works by feeding inputs and evaluating outputs. However, in some cases, the developers may want to check if an API request updates the database or triggers another request. 

For the API test, you need an API endpoint, which is basically a URL.  Next, you can set the HTTP headers as per the test. There are different types of HTTP requests, such as GET, PUT, POST, and DELETE. With each HTTP request, the required data is sent to the endpoint. 

The response code and contents are validated when the request is received. Also, the HTTP headers that describe the content type, access control, or server are validated.

When there is a sequence of API calls, parts of the response are employed for the next API call. For instance, if it is a POST request, it might return an identifier. So a subsequent GET request can be used to verify that the response contains this identifier.

API Testing Using the Postman GUI 

As mentioned before, Postman is an API client and can be used to develop and test APIs effectively. Follow these steps to automate API testing using Postman:

Step 1: Start a new API or import an existing API definition. You need to click on the API sidebar and go to the Import option. This option comprises all details regarding the API, such as its name and the method type. You can import the API definitions from a local directory or a file, a URL, a code repository, raw text, or an API gateway.  

Step 2: Go to the Variable tabs and declare the common variable API key. You can also declare API values such as authentication token and server base URL. 

Step 3: You can write test scripts in Postman using JavaScript. To create your first test script, you must go to the Tests tab and input the JavaScript code: pm. test("Status code is 200", function () { pm. Now, it will check the response code as 200. 

Step 4: Once you are done with the test script, the next step is to click the send button to call the API. Now the application will call the API and get the responses. Once the responses are received, the test case will execute the scripts automatically, and you can view the test results. (Pass/Fail). 

For more information about using Postman for API testing, refer to this tutorial.

How To Improve Your Automated Tests

Automation software offers monitoring features that help you provide specifications regarding the test schedule. It also enables you to integrate email notifications into the process. You can refine the tests by checking the errors at any time and trying to resolve the issue. Many other testing tools also offer similar capabilities.

Additionally, ensure that your enterprise has a solid framework that standardizes the testing practice for all testers. Standardization enables you to have specific guidelines that are immensely helpful to all the new testers as and when you scale your teams.

Leverage DreamFactory’s Test Automation Capabilities

Did you know that lack of testing is the primary hurdle when it comes to digital transformation? API testing helps assess an API's functionality, reliability, and security and is integral to the API development lifecycle. DreamFactory’s robust platform enables you to create comprehensive test suites that ensure your API performs well while dealing with various expected and unexpected requests.

Help your development teams focus on high-value strategic work and deliver customer experiences with this seamless open-source platform. Start your 14-day free trial today to see how DreamFactory can help your enterprise with its test automation capabilities.