Setting variables from response in Postman - Test Execution Trace

Test Overview

This test sends an API request and sets a Postman environment variable from the JSON response. It verifies that the variable is correctly set for later use.

Test Code - Postman

Postman

pm.test("Set variable from response", function () {
    const jsonData = pm.response.json();
    pm.environment.set("userId", jsonData.id);
    pm.expect(pm.environment.get("userId")).to.eql(jsonData.id);
});

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Test starts and sends API request	Postman sends HTTP request to the API endpoint	-	PASS
2	Receives JSON response with user data	Response body contains JSON like {"id": 123, "name": "John"}	-	PASS
3	Extracts 'id' from response JSON and sets environment variable 'userId'	Environment variable 'userId' is set to 123	Check environment variable 'userId' equals response 'id'	PASS
4	Assertion verifies 'userId' variable matches response 'id'	Variable 'userId' value is 123, matching response	pm.expect(pm.environment.get("userId")).to.eql(jsonData.id);	PASS

Failure Scenario

Failing Condition: Response JSON does not contain 'id' field or variable is not set

Execution Trace Quiz - 3 Questions

What does the test do after receiving the API response?

A Sets an environment variable from the response JSON

B Sends another API request immediately

C Deletes all environment variables

D Closes the Postman app

Key Result

Always verify that the response contains the expected data before setting variables, and assert the variable value to catch errors early.