Why Postman supports non-functional testing - Quick Recap

Recall & Review

beginner

What is non-functional testing?

Non-functional testing checks how well a system works, like its speed, reliability, and security, rather than what it does.

beginner

Why can Postman be used for non-functional testing?

Postman can test performance, security, and reliability of APIs by sending requests and checking response times, status codes, and data.

intermediate

How does Postman measure API performance?

Postman records response time for each API request, helping testers see if the API is fast enough under different conditions.

intermediate

What role do assertions play in Postman for non-functional testing?

Assertions check if API responses meet expected conditions like response time limits or correct status codes, ensuring quality beyond functionality.

intermediate

Can Postman test API security? How?

Yes, Postman can test security by sending requests with different authentication tokens and checking if unauthorized access is blocked.

What type of testing focuses on how well a system performs rather than what it does?

A Non-functional testing

B Functional testing

C Unit testing

D Integration testing

Non-functional testing checks qualities like speed and reliability, not specific functions.

Which Postman feature helps measure API response time?

A Response time metrics

B Code editor

C Environment variables

D Mock servers

Postman shows response time for each request, useful for performance testing.

How does Postman help test API security?

A By creating UI tests

B By editing API code

C By sending requests with different authentication tokens

D By generating reports only

Testing with various tokens checks if unauthorized access is prevented.

What is an assertion in Postman used for?

A To design UI layouts

B To write API documentation

C To create new API endpoints

D To verify API response meets expected conditions

Assertions check if responses are correct, including status and timing.

Which of these is NOT a non-functional testing aspect Postman supports?

A Performance

B User interface design

C Security

D Reliability

Postman tests APIs, not user interface design.

Explain why Postman is suitable for non-functional testing of APIs.

Think about what qualities besides functionality Postman can check.

Describe how you would use Postman to test API performance and security.

Consider sending different requests and checking their results.

Practice

1. Why does Postman support non-functional testing like checking API speed and stability?

easy

A. To write complex backend code

B. To only test the API's user interface design

C. To replace functional testing completely

D. To ensure APIs work well under different conditions and meet quality standards

Solution

1. Step 1: Understand non-functional testing purpose

   Non-functional testing checks qualities like speed, stability, and security, not just if the API works.

2. Step 2: Relate to Postman's role

   Postman helps test these qualities to ensure APIs perform well and are reliable before users use them.

3. Final Answer:

   To ensure APIs work well under different conditions and meet quality standards -> Option D

4. Quick Check:

   Non-functional testing = Quality checks [OK]

Hint: Non-functional means quality, not just function [OK]

Common Mistakes:

• Confusing non-functional with functional testing
• Thinking Postman only tests UI
• Believing Postman replaces all testing

2. Which JavaScript code snippet correctly measures API response time in Postman tests?

easy

A. pm.test('Response time is less than 200ms', () => pm.expect(pm.response.responseTime).to.be.below(200));

B. pm.test('Response time check', () => pm.response.responseTime < 200);

C. pm.expect(pm.response.time).to.be.above(200);

D. pm.test('Check time', () => pm.responseTime < 200);

Solution

1. Step 1: Identify correct Postman test syntax

   Postman tests use pm.test with a description and a function containing assertions using pm.expect.

2. Step 2: Check property and assertion correctness

   The correct property for response time is pm.response.responseTime, and to check below 200ms use .to.be.below(200).

3. Final Answer:

   pm.test('Response time is less than 200ms', () => pm.expect(pm.response.responseTime).to.be.below(200)); -> Option A

4. Quick Check:

   Correct syntax + property = pm.test('Response time is less than 200ms', () => pm.expect(pm.response.responseTime).to.be.below(200)); [OK]

Hint: Use pm.test with pm.expect and correct property [OK]

Common Mistakes:

• Using wrong property names like pm.response.time
• Missing pm.test wrapper
• Incorrect assertion methods

3. Given this Postman test code, what will be the test result if responseTime is 150ms?

pm.test('API is fast', () => {
  pm.expect(pm.response.responseTime).to.be.below(200);
});

medium

A. Test fails because 150ms is not below 200ms

B. Test throws an error due to syntax

C. Test passes because 150ms is below 200ms

D. Test is skipped automatically

Solution

1. Step 1: Understand the assertion condition

   The test checks if responseTime is below 200ms using .to.be.below(200).

2. Step 2: Compare given responseTime value

   150ms is less than 200ms, so the condition is true and the test passes.

3. Final Answer:

   Test passes because 150ms is below 200ms -> Option C

4. Quick Check:

   150 < 200 = Pass [OK]

Hint: Check if value meets condition literally [OK]

Common Mistakes:

• Misreading 'below' as 'above'
• Assuming syntax error without checking code
• Thinking test skips automatically

4. Identify the error in this Postman test code for checking API security headers:

pm.test('Security headers present', () => {
  pm.expect(pm.response.headers.has('Content-Security-Policy')).to.equal(true
});

medium

A. Missing closing parenthesis in pm.expect statement

B. Incorrect header name used

C. pm.response.headers.has is not a function

D. pm.test requires a callback function

Solution

1. Step 1: Check syntax of pm.expect statement

   The pm.expect call is missing a closing parenthesis after .to.equal(true).

2. Step 2: Verify other parts

   Header name and pm.response.headers.has function are correct, and pm.test has a callback function.

3. Final Answer:

   Missing closing parenthesis in pm.expect statement -> Option A

4. Quick Check:

   Syntax error = Missing parenthesis [OK]

Hint: Count parentheses carefully in assertions [OK]

Common Mistakes:

• Assuming wrong header name
• Thinking pm.response.headers.has doesn't exist
• Ignoring missing parenthesis

5. You want to use Postman to check API stability by running a test multiple times and measuring if response times stay below 300ms consistently. Which approach best fits this non-functional testing goal?

hard

A. Manually send one request and check response time once

B. Use Postman Collection Runner to run the test repeatedly and write a test script to assert responseTime < 300ms each time

C. Write a test that only checks if status code is 200

D. Use Postman to test only API functionality, not response times

Solution

1. Step 1: Understand stability testing requirements

   Stability means consistent performance over multiple runs, so repeated tests are needed.

2. Step 2: Choose Postman feature and test script

   Collection Runner allows running tests multiple times; writing a script to check responseTime < 300ms each time fits the goal.

3. Final Answer:

   Use Postman Collection Runner to run the test repeatedly and write a test script to assert responseTime < 300ms each time -> Option B

4. Quick Check:

   Repeated tests + response time check = Use Postman Collection Runner to run the test repeatedly and write a test script to assert responseTime < 300ms each time [OK]

Hint: Use Collection Runner for repeated tests [OK]

Common Mistakes:

• Testing only once for stability
• Ignoring response time in tests
• Confusing functional with non-functional testing