The blog post discusses why developers should use API testing and how it is becoming increasingly important, particularly as microservices architecture gains popularity. This technique necessitates that application components work separately, each with their own data storage and commands. As a result, software components can be updated fast without disrupting the whole system, allowing consumers to continue using the application flawlessly.
Most microservices are based on application programming interfaces (APIs), which specify how to connect with them. APIs usually use REST calls over HTTP to simplify data sharing. Despite this, many testers still rely on user interface (UI) testing, particularly using the popular Selenium automation tool. While UI testing is required to ensure interactive functioning, API testing is more efficient and dependable. It enables testers to edit information in real time and detect flaws early in the development process, even before the user interface is constructed. API testing is also important for identifying security flaws.
To effectively test APIs, it is critical to understand the fundamentals. APIs are REST calls that retrieve or update data from a database. Each REST request consists of an HTTP verb (which specifies the action), a URL (which indicates the target), HTTP headers (which provide additional information to the server), and a request body (which contains the data, usually in JSON or XML). Common HTTP methods are GET (retrieving a record), POST (creating a new record), PUT (altering a record), PATCH (partially updating a record), and DELETE. The URL specifies which data is affected, whereas the request body applies to actions such as POST, PUT, and PATCH.
When a REST request is made, the server responds with HTTP headers defining the response, a response code indicating if the request was successful, and, in certain cases, a response body containing extra data. The response codes are categorized as follows: 200-level codes represent success, 400-level codes indicate client-side issues, and 500-level codes signify server-side faults.
To effectively test APIs, testers must first understand the types of REST queries supported by the API and any limitations on their use. Developers can use tools like Swagger to document their APIs. Testers should ask clarifying questions about available endpoints, HTTP methods, authorization requirements, needed data, validation limits, and expected response codes.
API testing often begins with creating requests via a user-friendly tool like Postman, which allows for easy viewing of results. The initial tests should focus on “happy paths,” or typical user interactions. These tests should include assertions to ensure that the response code is proper and that the delivered data is accurate. Negative tests should then be run to confirm that the application handles problems correctly, such as erroneous HTTP verbs, missing headers, or illegal requests.
Finally, the blog underlines the necessity of API testing and encourages engineers to transition from UI testing to API testing. This shift enables faster and more reliable testing, which aids in the detection of data manipulation issues and improves security.
Blog: https://simpleprogrammer.com/api-testing/
From the blog CS@Worcester – Matchaman10 by tam nguyen and used with permission of the author. All other rights reserved by the author.