Saving responses in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Postman test script?

Consider this Postman test script that saves a response value to an environment variable. What will be the value of the environment variable userId after running this test if the response body is {"id": 42, "name": "Alice"}?

Postman

pm.test("Save userId", function () {
    var jsonData = pm.response.json();
    pm.environment.set("userId", jsonData.id);
});

A 42 (number)

B undefined

C "42" (string)

D null

💡 Hint

Remember that Postman environment variables store values as strings.

Postman environment variables always store values as strings. Even though jsonData.id is a number (42), when saved using pm.environment.set, it is converted to the string "42".

❓ assertion

intermediate

Which assertion correctly verifies a saved response value in Postman?

You saved the response field token to an environment variable authToken. Which assertion correctly checks that authToken is not empty in a test script?

A pm.expect(pm.environment.get('authToken')).to.not.be.empty;

B pm.expect(pm.environment.authToken).to.exist;

C pm.expect(pm.environment.get('authToken')).to.equal(null);

D pm.expect(pm.environment.get('authToken')).to.be.undefined;

💡 Hint

Use the correct method to get environment variables and check for non-empty string.

To get an environment variable, use pm.environment.get('variableName'). To check it is not empty, use to.not.be.empty. Option A correctly does this.

🔧 Debug

advanced

Why does this Postman script fail to save the response value?

This script tries to save response.data.id to an environment variable but it does not work. What is the likely cause?

Postman

pm.test("Save ID", function () {
    var id = pm.response.data.id;
    pm.environment.set("userId", id);
});

A pm.environment.set requires a callback function.

B pm.response.data is undefined; should use pm.response.json() to parse JSON body.

C pm.response.data.id is a reserved keyword and cannot be accessed.

D pm.environment.set only accepts string literals, not variables.

💡 Hint

Check how to access JSON response body in Postman scripts.

Postman response object does not have a data property directly. To access JSON response data, you must parse it using pm.response.json(). So pm.response.data is undefined, causing the failure.

❓ framework

advanced

Which Postman feature allows saving response data automatically for later use in a collection run?

You want to save parts of the response from one request and use them in subsequent requests automatically during a collection run. Which Postman feature supports this best?

A Using the Postman Runner's built-in response caching

B Using Postman monitors to save responses externally

C Using the Postman console to copy response data manually

D Using environment or collection variables set in test scripts

💡 Hint

Think about how variables can be shared across requests in a collection.

Setting environment or collection variables in test scripts allows saving response data that can be used in later requests during a collection run. This is the standard way to pass data between requests.

🧠 Conceptual

expert

What is a key limitation when saving large response bodies as Postman environment variables?

When saving large JSON response bodies as environment variables in Postman, what is a common limitation you must consider?

A Environment variables have size limits and large data may be truncated or cause errors

B Environment variables automatically compress large data to save space

C Environment variables can only store numeric values, not JSON strings

D Postman converts large JSON to XML when saving as environment variables

💡 Hint

Think about storage limits in Postman environment variables.

Postman environment variables have size limits (usually a few KB). Saving very large response bodies can lead to truncation or errors. They do not compress or convert data automatically.