Environment variables in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Purpose of Environment Variables in Postman

What is the main purpose of using environment variables in Postman?

A To store values that can change between different environments like development, testing, and production

B To write JavaScript code that runs before sending a request

C To create collections of API requests for sharing

D To generate random data for testing

💡 Hint

Think about how you can reuse the same request with different settings.

Environment variables allow you to store values that differ between environments, such as URLs or API keys, so you can switch easily without changing each request.

❓ Predict Output

intermediate

Output of Accessing Environment Variable in Test Script

What will be the output of the following Postman test script if the environment variable userId is set to 12345?

Postman

const userId = pm.environment.get('userId');
console.log(`User ID is: ${userId}`);
pm.test('Check userId', () => {
    pm.expect(userId).to.eql('12345');
});

A User ID is: 12345 (test passes)

B User ID is: undefined (test fails)

C User ID is: 12345 (test fails)

D SyntaxError due to incorrect pm.expect usage

💡 Hint

Check how pm.environment.get retrieves the variable and how the assertion compares values.

The environment variable userId is correctly retrieved and equals '12345', so the console logs the value and the test passes.

❓ locator

advanced

Correct Locator for Environment Variable in Postman Pre-request Script

Which of the following lines correctly sets an environment variable named token to the value abc123 in a Postman pre-request script?

A pm.globals.set('token', 'abc123');

B pm.variables.set('token', 'abc123');

C pm.environment.set('token', 'abc123');

D pm.request.set('token', 'abc123');

💡 Hint

Remember environment variables are set with a specific Postman API method.

The correct method to set an environment variable is pm.environment.set. Other options set different scopes or are invalid.

❓ assertion

advanced

Assertion to Verify Environment Variable Exists and Is Not Empty

Which assertion correctly verifies that the environment variable sessionId exists and is not an empty string in a Postman test script?

Postman

const sessionId = pm.environment.get('sessionId');

A pm.expect(sessionId).to.equal(null);

B pm.expect(sessionId).to.exist.and.to.be.empty;

C pm.expect(sessionId).to.be.undefined;

D pm.expect(sessionId).to.be.a('string').and.not.empty;

💡 Hint

Check how to assert a string is not empty and exists.

Option D checks that sessionId is a string and is not empty, which confirms it exists and has a value.

🔧 Debug

expert

Debugging Environment Variable Not Updating in Postman

You have this test script in Postman:

pm.environment.set('count', 1);
let count = pm.environment.get('count');
count++;
pm.environment.set('count', count);
console.log('Count is:', count);

After running the request multiple times, the count variable always logs 2. What is the most likely reason?

A Postman does not allow updating environment variables in test scripts

B The environment variable <code>count</code> is being reset to 1 every time before incrementing

C The <code>count++</code> operation does not change the variable value

D The console.log statement is incorrect and does not show updated value

💡 Hint

Look at the first line and how it affects the variable on each run.

The script sets count to 1 at the start every time, so incrementing always starts from 1, never accumulating.