Load testing basics (Postman) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Load Testing Purpose

What is the main goal of load testing in Postman?

A To check how the system behaves under expected user load

B To find security vulnerabilities in the API

C To verify the correctness of API responses

D To test the user interface responsiveness

💡 Hint

Think about what happens when many users use the system at the same time.

Load testing measures system behavior under expected user load to ensure stability and performance.

❓ Predict Output

intermediate

Interpreting Load Test Results in Postman

After running a load test with 50 virtual users for 1 minute in Postman, the average response time is 1200 ms, and error rate is 0%. What does this indicate?

A The API is not responding because response time is too high

B The API is failing because response time is over 1000 ms

C The test failed because error rate should not be zero

D The API handles the load well with no errors and acceptable response time

💡 Hint

Consider what a 0% error rate means and if 1200 ms is acceptable.

An average response time of 1200 ms with zero errors means the API is stable and handles the load well.

❓ assertion

advanced

Correct Assertion for Response Time in Postman Load Test

Which Postman test script assertion correctly checks that the response time is less than 2000 milliseconds during a load test?

Postman

pm.test('Response time is less than 2000ms', function () {
    // Fill in assertion here
});

A pm.expect(pm.response.responseTime).to.be.below(2000);

B pm.expect(pm.response.time).to.be.above(2000);

C pm.expect(pm.response.responseTime).to.equal(2000);

D pm.expect(pm.response.time).to.be.belowOrEqual(2000);

💡 Hint

Look for the correct property name and assertion method to check less than a value.

The property pm.response.responseTime holds the response time in ms. The assertion to.be.below(2000) checks it is less than 2000 ms.

🔧 Debug

advanced

Identifying Load Test Script Error in Postman

Given this Postman test script snippet for load testing, what error will occur?

Postman

pm.test('Status code is 200', () => {
    pm.expect(pm.response.status).to.eql(200);
});

A TypeError because pm.response.status is undefined

B No error, test passes if status is 200

C AssertionError because status code is not 200

D SyntaxError due to arrow function usage

💡 Hint

Check the correct property name for status code in Postman response object.

The correct property for status code is pm.response.code, not pm.response.status (which returns the status text like "OK"). Expecting the status text to equal 200 causes an AssertionError.

❓ framework

expert

Configuring Load Test in Postman Runner

Which sequence correctly describes the steps to configure a load test with 100 virtual users running for 2 minutes in Postman Collection Runner?

A 1,2,4,3

B 1,2,3,4

C 1,3,2,4

D 2,1,3,4

💡 Hint

Remember that delay is the wait time between requests, and iterations control how many times the collection runs.

First select the collection, then open Runner, set iterations (to control number of runs), then set delay (to control wait time between requests).

Practice

1. What is the main purpose of load testing in Postman?

easy

A. To check how many users the app can handle at the same time

B. To find syntax errors in API requests

C. To test the UI responsiveness of the app

D. To verify database schema correctness

Solution

1. Step 1: Understand load testing goal

   Load testing is about simulating many users to see how the app performs under stress.

2. Step 2: Match with Postman usage

   Postman can send multiple requests to simulate users, so it helps check app capacity.

3. Final Answer:

   To check how many users the app can handle at the same time -> Option A

4. Quick Check:

   Load testing = user capacity check [OK]

Hint: Load testing = many users at once [OK]

Common Mistakes:

• Confusing load testing with syntax checking
• Thinking load testing checks UI only
• Mixing load testing with database tests

2. Which Postman feature allows you to run multiple requests repeatedly for load testing?

easy

A. Postman Runner

B. Postman Console

C. Postman Monitor

D. Postman Collection Editor

Solution

1. Step 1: Identify Postman features for running requests

   Postman Runner lets you run a collection of requests multiple times.

2. Step 2: Match feature to load testing

   Running requests repeatedly simulates load, so Runner is the correct tool.

3. Final Answer:

   Postman Runner -> Option A

4. Quick Check:

   Repeated runs = Postman Runner [OK]

Hint: Use Runner to repeat requests [OK]

Common Mistakes:

• Choosing Console which is for debugging
• Confusing Monitor with scheduled tests
• Thinking Collection Editor runs requests

3. Consider this Postman Runner setup: you run 100 iterations with 10 requests each. How many total requests are sent?

medium

A. 100

B. 10

C. 1000

D. 110

Solution

1. Step 1: Understand iterations and requests per iteration

   Each iteration runs 10 requests, and there are 100 iterations total.

2. Step 2: Calculate total requests

   Total requests = 100 iterations * 10 requests = 1000 requests.

3. Final Answer:

   1000 -> Option C

4. Quick Check:

   100 x 10 = 1000 [OK]

Hint: Multiply iterations by requests per iteration [OK]

Common Mistakes:

• Adding instead of multiplying
• Confusing iterations with requests
• Ignoring requests per iteration

4. You tried to run a load test in Postman Runner but only one request was sent repeatedly instead of the whole collection. What is the likely mistake?

medium

A. You forgot to save the collection

B. You selected a single request instead of the full collection

C. You used Monitor instead of Runner

D. You set iterations to 1

Solution

1. Step 1: Analyze the problem

   Only one request runs repeatedly, not the whole collection.

2. Step 2: Identify cause

   This happens if you run a single request in Runner instead of the entire collection.

3. Final Answer:

   You selected a single request instead of the full collection -> Option B

4. Quick Check:

   Single request run = wrong selection [OK]

Hint: Always select full collection for load test [OK]

Common Mistakes:

• Thinking iterations = 1 causes this
• Confusing Monitor with Runner
• Assuming saving fixes request selection

5. You want to perform a heavy load test beyond Postman's Runner limits. Which approach is best?

hard

A. Increase iterations in Postman Runner to 10,000

B. Use Postman Console to debug requests

C. Run Postman Monitor continuously for 24 hours

D. Use Newman in combination with a load testing tool like Apache JMeter

Solution

1. Step 1: Understand Postman Runner limits

   Postman Runner is good for basic load but not for very heavy or distributed load testing.

2. Step 2: Identify best heavy load testing method

   Newman can run collections from command line and can be integrated with tools like JMeter for heavy load.

3. Final Answer:

   Use Newman in combination with a load testing tool like Apache JMeter -> Option D

4. Quick Check:

   Heavy load = Newman + load tool [OK]

Hint: Combine Newman with load tools for heavy tests [OK]

Common Mistakes:

• Trying to increase Runner iterations too high
• Using Monitor for load testing
• Using Console for load testing