Quite against the popular notion, it is seen that APIs failure is the reason behind 90 percent of all failures in today’s applications. The truth is that APIs can crash and even if they do not, they perform inadequately sporadically, causing the app either to hang to sometimes crash completely. To understand this problem, we need to understand what an API does. API is a way through which a programmer communicates with an external service and asks the app to perform a task. For example, if you are using a travel service application like Trivago or Booking Dot Com, you might wonder how these applications have the most updated information about all the hotels. This is accomplished via an API, which takes your query and returns with an answer. However, if this API fails or performs poorly, the application itself will stop working properly.
Change in Software Version
It is not necessary that an API that worked in previous versions of a software program will also work in the current version. The syntax, formatting, arguments may need to be changed to work perfectly in the new version. It is seen that 80 percent of the entire web and mobile traffic goes through APIs. Hence, it is necessary to End-to-End test the API to ensure its smooth functioning.
Response to Hang-ups
In case an application depends on a response from an external server, there are high chances that the app will hang up in case of timeouts, failed connects, overload of requests on the server, etc. Thereby, the API must know how to deal with such cases and provide the app users with an appropriate response.
Bad Data
It is not always necessary that the data gathered by the API from an external source will be in a form that the API understands. Hence, the API should be made in a way that it can return relevant responses in such cases. There are other cases as well where an API might fail to perform, which is reflected in the poor behavior of the application. All these shortcomings can be solved by End-to-End API testing.
End-to-End API Testing
End-to-end API testing is a way to test an API flow from start to end. Its aim is to simulate a real-life application usage scenario and find out the breakpoints. An E2E test covers the calling of several APIs in sequence like logging in to an e-commerce website, selecting a product, going to the cart for checkout, applying a coupon if any, and making payment securely. This shows that most of the functional and business logic of the majority of applications are driven by APIs.
An autonomous E2E API testing can solve this problem by monitoring all customer queries or API-provided inter-services calls like creating a log of complete API data of requests that includes everything except API responses.
These registered logs are used to simulate the real sequence of steps taken by the user. This is what testing API in the end-to-end user journey is.
When these E2E API tests are completed, they show a complete list of all changes except the false positives. The important thing to note here is that the API testing team never writes tests, maintains or updates them in the entire scheme. Such tests are extremely valuable as they reflect the actual user experience.
It is seen that API failures contribute to most of the application issues. Hence, testing API end-to-end is extremely necessary in order to develop a bug-free application. By fixing API issues, a developer can optimize the application by a fair degree. And E2E API testing does the work by creating data that simulates the real-life user journey through the application.