Postman Tutorial: API Testing Basics and Automation

steps

1. Download or Open Postman: Use the web-based version or download the standalone app for your operating system.
2. Sign Up for an Account: Sign up or log in to your Postman account for saving collections and accessing collaboration features.
3. Switch to Dark Theme (Optional):
   • Click the gear icon in the top-right of the app.
   • Navigate to the Settings > Themes tab.
   • Select the "Dark" theme.

steps

1. Retrieve API Documentation: Obtain the details of the API you want to test, including endpoint URLs and any required parameters or authentication details.
2. Send a GET Request:
   • Open a new tab in Postman.
   • Enter the API endpoint in the request field.
   • Set the method to GET (default selection).
   • Click Send to fetch the response.
3. Analyze the Response:
   • Check the status code (e.g., 200 for success).
   • Review the response body for correctness.
4. Use Variables for Reusability:
   • Click the "Environment" quick look eye icon to view/manage variables or access Manage Environments.
   • Define variables (e.g., {{base_url}}).
   • Replace hardcoded parts of the URL or body with {{variable_name}}.

steps

1. Define a Test in the Tests Tab:
   • Select the Tests tab below your request.
   • Write a simple test using Postman’s scripting environment, for example:
     javascriptCopy

     pm.test("Status code is 200", function () {
         pm.response.to.have.status(200);
     });

2. Parse and Assert:
   • Parse the response JSON and assert properties:
     javascriptCopy

     const response = pm.response.json();
     pm.test("Response status is OK", function () {
         pm.expect(response.status).to.eql("ok");
     });

3. Test Requests in a Collection:
   • Apply similar tests to other requests in the collection.
   • Ensure each test verifies critical aspects like status codes and response structure.

steps

1. Open the Collection Runner:
   • Click Run at the top right of the Postman interface or select Runner from the bottom menu.
2. Choose a Collection:
   • Drag and drop the collection you want to run into the Runner.
   • Reorder requests if necessary.
3. Configure Execution:
   • Set the iteration count (e.g., run multiple times).
   • Enable Save responses to help debug errors.
4. Run the Collection:
   • Click Start Run and inspect results for passed or failed tests.