Load testing basics (Postman) - Test Execution Trace

Test Overview

This test simulates multiple users sending requests to an API endpoint using Postman to check how the system handles load. It verifies that the API responds successfully under the simulated load.

Test Code - Postman

Postman

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});

// In Postman Collection Runner or Postman Load Testing, set iterations to 50 to simulate load

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts in Postman Collection Runner with 50 iterations	Postman is ready to send requests repeatedly to the API endpoint	—	PASS
2	Postman sends the first API request	API server receives the request and processes it	—	PASS
3	Postman receives the response for the first request	Response status code is 200 OK	Check that response status code is 200	PASS
4	Postman sends remaining 49 requests sequentially	API server processes each request under load	—	PASS
5	Postman receives responses for all requests	All responses have status code 200	Verify all responses have status 200	PASS
6	Test completes and Postman shows summary report	Report shows 50 requests sent, all passed	Confirm no failed requests	PASS

Failure Scenario

Failing Condition: API server returns status codes other than 200 during load

Execution Trace Quiz - 3 Questions

What does the test verify in this load test?

A That the API response time is less than 1 second

B That the API returns data in JSON format

C That the API responds with status 200 under load

D That the API endpoint URL is correct

Key Result

Always verify the API response status codes during load testing to ensure the system handles multiple requests without errors.

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