Looping in flows in Postman - Test Execution Trace

Test Overview

This test checks if a Postman collection correctly loops through multiple user IDs and fetches their details one by one. It verifies that the API response for each user contains the expected user ID.

Test Code - Postman

Postman

const userIds = [1, 2, 3];
let currentIndex = pm.environment.get('currentIndex') || 0;
const userId = userIds[currentIndex];

pm.sendRequest(`https://jsonplaceholder.typicode.com/users/${userId}`, function (err, res) {
    pm.test("Loop through user IDs and verify response", function () {
        pm.expect(err).to.be.null;
        pm.expect(res).to.have.property('code', 200);
        const jsonData = res.json();
        pm.expect(jsonData.id).to.eql(userId);
    });

    currentIndex++;
    if (currentIndex < userIds.length) {
        pm.environment.set('currentIndex', currentIndex);
        postman.setNextRequest(pm.info.requestName);
    } else {
        pm.environment.unset('currentIndex');
        postman.setNextRequest(null);
    }
});

Execution Trace - 13 Steps

Step	Action	System State	Assertion	Result
1	Test starts and reads currentIndex from environment (initially 0)	Environment variable 'currentIndex' is 0 or undefined	-	PASS
2	Sends GET request to https://jsonplaceholder.typicode.com/users/1	Browser/Postman sends request for user ID 1	Response status code is 200	PASS
3	Checks response JSON contains id = 1	Response JSON has user data with id 1	jsonData.id equals 1	PASS
4	Increments currentIndex to 1 and sets environment variable	Environment variable 'currentIndex' is now 1	-	PASS
5	Sets next request to the same request to loop	Postman will run the same request again	-	PASS
6	Sends GET request to https://jsonplaceholder.typicode.com/users/2	Browser/Postman sends request for user ID 2	Response status code is 200	PASS
7	Checks response JSON contains id = 2	Response JSON has user data with id 2	jsonData.id equals 2	PASS
8	Increments currentIndex to 2 and sets environment variable	Environment variable 'currentIndex' is now 2	-	PASS
9	Sets next request to the same request to loop	Postman will run the same request again	-	PASS
10	Sends GET request to https://jsonplaceholder.typicode.com/users/3	Browser/Postman sends request for user ID 3	Response status code is 200	PASS
11	Checks response JSON contains id = 3	Response JSON has user data with id 3	jsonData.id equals 3	PASS
12	Increments currentIndex to 3 and unsets environment variable	Environment variable 'currentIndex' is removed	-	PASS
13	Sets next request to null to stop looping	Postman stops running the request	-	PASS

Failure Scenario

Failing Condition: API returns a status code other than 200 or response JSON id does not match expected userId

Execution Trace Quiz - 3 Questions

What causes the test to loop through multiple user IDs?

A Setting 'postman.setNextRequest' to the same request name

B Using a for loop inside the test script

C Calling pm.sendRequest multiple times synchronously

D Setting environment variable 'currentIndex' to zero

Key Result

Use environment variables and 'postman.setNextRequest' to create loops in Postman tests, allowing repeated requests with different data in a controlled flow.