APIs being at the core of the software required appropriate testing and testing methods. A number of testing methods satisfy the early need to recognize and eliminate errors, which could possibly be a major hurdle in further development. Today, As a load testing company, our Technical experts explore the steps of How to Use Postman to test API and why API Testing is needed.
What is Postman?
In simple words, Postman is a computer application used for API testing. Postman sends an API request to the web server and receives the response, whatever it is. No extra work or setting up of a framework is required while sending and receiving requests in Postman. Extensively used by Testers and Developers for better testing of applications. Easy to integrate with your Continuous Integration (CI) & Continuous Development Pipeline.
What makes Postman Useful?
Postman with its number of features and ease of work has been used by millions of testers. Using its simple and user-friendly interface, you can easily send requests, just fill in the required data, select the HTTP method, and hit the “Send” button. Another widely used feature is Automation, which let you set up tests and write test suites.
Though it is free to use, Postman offers you a paid version with pro features like multiple-user access, Control over roles, access, SSO Authentication, etc. Allowing users to set up the required environment, write specifications and finally monitor every step, is all that makes Postman an ideal Testing Tool.
Download & Install Postman: Postman is available to download for free as it is an open-source project. It is as easy to download and install as any other computer application.
First, Go to https://www.postman.com/downloads/ and download it as per your system OS. Being cross-platform, it is available for Windows, Linux & Mac. And to make it easier, Postman now has a web version, in case you want to experience it on your web browser.
In case you wish to use the web version all you have to do create an account or log in with the existing one and you are ready to try.
Moving on, once your download is complete you can begin with installation by simply double-clicking the application.
Soon enough it will ask for your Postman Account details, if you don’t have an account you can create one right away, else login as usual.
Once you are in, it will ask for your preferences, workspace, and where you are. You now are on the start-up page.
Read also: What is API Testing and Why API Testing is Needed?
How Use Postman to Automate API Test?
Postman is a User-friendly testing tool that allows you to send API requests in fewer steps. To begin with, on your landing page, you will see a number of buttons that are designed for easy navigation.
Clicking on the New button, you can create a new request or collection. When on the new screen, HTTP Requests such as POST, GET, DELETE, etc are listed and can be selected as per need. Next to that is the Request URL, where you are expected to enter the endpoint URL, and at the end of the line is the Send button, which upon clicking will send the request to the intended URL and receive the response.
This is the basics of how to use the Postman, but Postman has a number of other features that are used for better testing. Following the Send button, the Save button allows you to save the current request so as not to lose any changes. Params, where parameters are entered in Key Value format,
Authorization is required when you are dealing with URLs that are not publicly open and for that purpose bearer, token, or User name & Password are used. Depending on the requirement, Headers with content types such as JSON can be set. The body allows you to develop customized details probably for the POST request. Pre-request Scripts are the scripts that are executed prior to the request, with the aim to make sure that the environment is set as per need so that further testing is done properly. The test consists of the script which is executed while the request is under process, these help you in verifying the status of the response and other points.
Import allows you to import an existing collection while Runner allows you to execute automation tests.
Automating API Testing can be divided into four basic steps, starting with Manual Testing of the APIs, then understanding the API’s response received, based on the previous two steps you can now write test suites and finally execute these test suites from different endpoints.
Basically, test suites are written or created as per API requirements of parameters and other necessary details and these test suites are executed over and over again, from various endpoints. These test scripts are written in JavaScript and can be executed before the request is made and after a response is received to the request made. A number of snippets are available for you to get started with the test.
Now, for the final step, all you have to do is send the request manually, but this time once the response is received for the request, Postman will automatically run the test written. The test Results tab shows you the results of the test.
This is the simplest example of automating a test in Postman, with added test suites and multiple requests along with parameters and required authorization, you can execute complex tests.
Why Automate API Testing is important?
For any software to be able to work as expected needs to undergo a testing phase for better service and with the involvement of API, which is the core and most important part of a system, it is essential that these APIs are tested through every possible endpoint and implementing automation in API testing ensures that every endpoint is tested and possible bugs are caught quickly.
Automation helps in case of repeated testing is required over a single module, allowing you to reuse a test suite. Averting possible human errors while testing is achieved through automation testing.
End Note
With features like the use of Collections, Test Suites, Continuous Integration, and Storage of calls, Postman is a choice of tool for API testing. Though Postman allows you to use it without an account, it is recommended to have an account as it will save your work.
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