API Testing — Benefits, Challenges, Best Practices, and Tools

Most software couldn’t exist in the absence of APIs. It’s not just access to the data we need, but it’s also that many other APIs that we depend on to do nitty gritty work to make software go.

To send SMS there is Twilio, to find places for food there is Yelp, for maps, there is Google maps api and so on. Hence, there is an API for just about anything you can imagine.

What is an API?

The term API stands for Application Programming Interface. It acts as a mediator that helps applications to communicate with one another.

API enacts a bunch of operations that can be used by the development team, which allows them to save time by taking advantage of a platform’s implementation to do the essentials. This helps lessen the amount of code developers need to create, and also helps create more stability across apps for the same platform.

Every time when you shop online, order food, check a map OR book a flight on your smartphone, you are making use of APIs to pull details from respective servers.

APIs also help to control hardware devices with the software application and so, APIs play an important role in security. Thus, API Testing plays a vital role in delivering quality software. It requires smooth API calls for an effortless application.

Why to Test APIs?

APIs have data and they function as bridges connecting application and device, hence it is critical to test APIs to ensure data is represented correctly.

Testing the API clears a lot of issues in the application which may arise at an indefinite time in the future.

Types of Bugs that API Testing Detects

With the API testing, It is likely to find potential bugs which may not be detected while testing UI, even if the UI calls the underlying API when used. The type of issues that could be tracked down when performing the API testing phase are:

• Security Issues
• Unused flags
• Missing or duplicate functionality
• Reliability Issues
• Multi-threading issues
• Performance Issues
• Improper errors/warning to a caller
• Incorrect handling of valid argument values
• Structure correctness for Response data (Json or XML)
• Security Issues

Challenges While Performing API Testing

To make API testing a prominent practice, it is important to understand that it helps reinforcing test coverage and reduce risks across the interfaces. To test API is as going beyond the GUI layer to scrutinize application to its core. Benefits come with challenges, and so with APIs, a few of the major challenges are listed here.

1. Understanding of the business application logic

Typically, APIs have a number of guidelines about usage such as copyright, storage and display policies. APIs are developed purely on business logic. Henceforth, the dearth of knowledge and acknowledgement of these guidelines and business logic among API testers lead to vagueness regardless of the test objective.

2. Impact of change

The new version of an API will likely hamper the entire application. As there are multiple dependent components, carrying out a change is often elevated to risk and uncertain in terms of its executions.

3. Management of test data

APIs are all about data and constructive testing demands more of the data for it has numerous parameters. To maintain such a huge amount of data and ensure that the data is serviceable is a big challenge for API testers.

Benefits of Testing APIs

Smart organizations take convenience in testing API before deploying the changes to the production environment. To confirm the software application meets requirements, it is necessary to test in both staging and development environments. Here are some benefits of testing APIs:

• A key benefit of API testing is having access to the application without a user interface and thus early identification of code-level issues which helps in earlier test maintenance.
• It is completely independent of any particular programming language since it requires data exchange using XML or JSON.
• API testing is faster and easy to perform as it doesn’t require GUI to be readily available.
• API testing adds good coverage to the core functionality and leads to reduced testing costs.

Best Practices For Testing APIs

It’s crucial to test the user’s approach on how they are going to interact with the application’s user interface. Therefore, the key practices of API testing can surpass the coverage of the test cycle, shield resources and result in speedy and efficient releases.

Here are some best practices for testing APIs:

• The first step to begin is to perform a smoke test before proceeding with the functional test of the APIs.
• Perform testing to check boundary value conditions and acceptance.
• Use exact conditions in the API testing phase.
• Save API response for future use.
• Perform security testing.
• Never forget to perform negative testing.

Tools Used for API Testing

A great deal of software’s is available in the market for API Testing, out of which some are commercial where some are open source. Mentioning few of the tools here:

Open-Source API Testing Tools:

• JMeter
• Rest-Assured
• Citrus Framework

Commercial API Testing Tools:

• Katalon Studio
• SoapUI
• Postman

One of the reliable and most used platforms that allow us to develop as well as test Rest APIs is Postman.

Postman is being used in masses, has numerous facets and is easy to work with. It has a straightforward user- interface that will ease sending requests, fill in required test data, select the HTTP method and hit the “Send” button.

Another feature being used extensively is API Automation, which lets you set up tests and write test suites.

Let’s explore the Postman tool and its features.

• New — To create a new request, collection, or environment.
• Import — To import a collection or environment. It is easy to import from file, folder or link.
• Open New — Open a new tab, Postman Window or Runner Window by clicking this button.
• My Workspace — To create a new workspace for self or as a team.
• Invite — Amalgamate on a workspace by inviting team members.
• History — Requests that are made in the past shall be dis[played in History.
• Collections — To create collections. Each collection can have sub folders and multiple requests.
• Request tab — Display title of the request. For requests that are made without titles, it displays “Untitled Request”.
• HTTP Request — A list of requests will be displayed in dropdown, such as GET, POST, COPY, DELETE, etc. the most common requests used widely in Postman are GET and POST.
• Request URL — This is the location of the API where the request is being sent. Also known as an endpoint.
• Save — To save the changes if made in the request.
• Parameters — The key value pairs should be written in the parameter section.
• Authorization — This is required to access APIs. It could be in the form of a bearer token, username and password, etc.
• Headers — This is to set a header such as content type JSON depending on the needs of the organization.
• Body — This is where the details can be updated in a request.
• Pre-request script and Tests — Code added under the Pre-request Script tab will execute before your request is sent, and code added under the Tests tab will execute after your response is received. A list of tests and whether the test has passed or failed will be displayed in the Tests. A boolean that evaluates to true is a passing test, and a Boolean that evaluates to false is a failing test.

POSTMAN is available as an extension of Chrome and can be added from here.

Conclusion

API test requires a distinctive set of conditions and inputs, which obstruct the foundering of the application. These API tests help eliminate such vulnerabilities from the software under test.

We at MindInventory have team of experienced and qualified software testing professionals who help You build flawless and high quality products with complete focus on end-users requirements. Check out some of the amazing work that we do at MindInventory and how we help build awesome products for people around the world.