This article is meant to provide a short and comprehensive guide on how to use Postman. Without this tool, a QA couldn’t live long and prosper during the troubled times a Sprint leads to.

What is Postman?

In a nutshell, it’s a tool used in development and testing. It’s one of the most powerful tools a QA could use. 

It comes in handy when there’s no UI (yet) or when we validate an API by testing all sorts of values and fields. You can send a request and examine the response without using a terminal (yay!).

What do I need?

  1. Download Postman from their official Website – https://www.postman.com/downloads/
  2. Install and set it up based on the recommendations. 
  3. Scroll down, and let’s see what we can do!

Getting started:

Let’s briefly go through the UI first:

Screenshot 2020 03 20 at 20.37.59

I’ve marked the sections we need to pay close attention to. Here’s a short description of each part:

1 – The drop-down will let you select the Method (e.g., GET, POST, PATCH, etc.).

2 – This text box is where we enter the URL we need to make the request to.

3 – The “Send” button will perform our request.

4 – This section is where more “details” can be added. We can include a body for POST requests, for example, or maybe some Headers;

5 – In this section, we can see the response. On the top right side of this part, we’ll see the status code, the size of the request, and the time it took to be completed.

Now, what do we do with this information?

For starters, we can change the Method. 

The most common methods used are POST, GET, PATCH, and DELETE. Most of the GET requests do not require a body, although the other methods do in most cases. Also, not all the endpoints support all the possible methods.

Next, we can add Parameters, Headers, different types of Body, or Authentication details. This will require more knowledge about what a request needs and how it works. Maybe your endpoint will not return a 200 status code without proper Authentication. That’s what you’ll have to find out!

Copy as cURL:

This guide wouldn’t be complete without presenting the Import – Paste Raw Text function.

It will come in handy if you need to test a request quickly and don’t know where to start.

Here are the steps:

  1. Open the DevTools of your testing browser and go around the request – you’ll need to identify it.
  2. Right-click on your request and click on “Copy as cURL.”
  3. Now, go to Postman, click on “Import,” select “Paste Raw Text,” paste your request there and click on the “Import” button.

From this step forward, the sky is the limit! 

And the non-200 status codes for which you’ll want to get ready to add tickets.

Tips for QA:

  • After performing a POST, do a GET and check the response. It should contain all the data from the POST request (this is the quickest way to check if the endpoint works as it should).
  • Edit and change the JSON to try to trick/break the client.
  • If the validation on the Backend side works, make sure to check it on the Frontend side as well – the validations on both sides should match.
  • Define and use Variables – this will let you quickly adapt a whole bunch of requests or tests that suffered changes.
  • Group and organize your requests using Folders and Sub-folders under the Collections section;
  • Integrate Tests to assess every response, request, and body quickly.
  • Add Scripts and use the Runner to create the most successive test suite.

Conclusions:

  • Postman is a day to day tool to any developer and a great help to any QA.
  • Learning, discovering, and using Postman will not only be quick and easy but will come in handy sooner than you think.
  • Postman allows for repeatable and reliable tests that can be automated and used in a variety of environments.
  • Even though at the beginning, creating an API test suite looks like it’s a titanic work, it will pay off in the end!

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