Variable syntax ({{variable}}) in Postman - Test Execution Trace

Test Overview

This test verifies that a Postman request correctly uses the variable syntax {{variable}} to substitute environment variables in the URL and headers. It checks that the request sends with the expected values and receives a successful response.

Test Code - Postman Test Script

Postman

pm.test("Variable substitution works", function () {
    // Access environment variable
    const baseUrl = pm.environment.get("baseUrl");
    const apiKey = pm.environment.get("apiKey");

    // Construct expected URL
    const expectedUrl = `${baseUrl}/users`;

    // Check request URL uses variable substitution
    pm.expect(pm.request.url.toString()).to.eql(expectedUrl);

    // Check header uses variable substitution
    const authHeader = pm.request.headers.get("Authorization");
    pm.expect(authHeader).to.eql(`Bearer ${apiKey}`);

    // Check response status
    pm.response.to.have.status(200);
});

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts	Postman environment variables 'baseUrl' and 'apiKey' are set	-	PASS
2	Postman sends request with URL containing {{baseUrl}} and header containing {{apiKey}}	Request URL is 'https://api.example.com/users', Authorization header is 'Bearer 12345abcde'	-	PASS
3	Test script retrieves environment variables 'baseUrl' and 'apiKey'	Variables retrieved: baseUrl='https://api.example.com', apiKey='12345abcde'	-	PASS
4	Test script checks that request URL matches expected URL	Request URL is 'https://api.example.com/users', expected URL is 'https://api.example.com/users'	pm.expect(pm.request.url.toString()).to.eql(expectedUrl)	PASS
5	Test script checks that Authorization header matches expected value	Authorization header is 'Bearer 12345abcde', expected is 'Bearer 12345abcde'	pm.expect(authHeader).to.eql(`Bearer ${apiKey}`)	PASS
6	Test script checks that response status is 200	Response status is 200 OK	pm.response.to.have.status(200)	PASS

Failure Scenario

Failing Condition: Environment variable 'baseUrl' or 'apiKey' is missing or not substituted correctly in the request

Execution Trace Quiz - 3 Questions

What does the test verify about the URL in the Postman request?

A That the {{baseUrl}} variable is correctly replaced with its value

B That the URL contains the literal string '{{baseUrl}}'

C That the URL is empty

D That the URL uses query parameters

Key Result

Always verify that environment variables are correctly defined and active in Postman before running tests that depend on {{variable}} substitution.