Response time assertions in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ assertion

intermediate

Check if response time is under 500ms

Which Postman test script correctly asserts that the response time is less than 500 milliseconds?

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B pm.test('Response time is less than 500ms', () => { pm.expect(pm.response.responseTime).to.be.below(500); });

C pm.test('Response time is less than 500ms', () => { pm.expect(pm.response.responseTime).to.be.above(500); });

D pm.test('Response time is less than 500ms', () => { pm.expect(pm.response.responseTime).to.equal(500); });

💡 Hint

Look for the correct property name and the correct comparison method.

Option B uses the correct property pm.response.responseTime and asserts it is below 500ms, which matches the requirement.

Option B incorrectly checks if response time is above 500ms.

Option B uses a wrong property pm.response.time which does not exist.

Option B checks for equality to 500ms, not less than.

❓ Predict Output

intermediate

Output of response time assertion failure

What will be the test result output if the response time is 600ms for the following Postman test?

pm.test('Response time under 500ms', () => { pm.expect(pm.response.responseTime).to.be.below(500); });

Postman

pm.test('Response time under 500ms', () => { pm.expect(pm.response.responseTime).to.be.below(500); });

A Test fails with syntax error

B Test passes successfully

C Test fails with assertion error: expected 600 to be below 500

D Test is skipped automatically

💡 Hint

Think about what happens when the actual response time is greater than the expected maximum.

The assertion expects the response time to be below 500ms, but the actual is 600ms, so the test fails with an assertion error showing the expected and actual values.

🔧 Debug

advanced

Identify the error in response time assertion script

Find the error in this Postman test script that checks response time:

pm.test('Response time check', () => { pm.expect(response.responseTime).to.be.below(300); });

Postman

pm.test('Response time check', () => { pm.expect(response.responseTime).to.be.below(300); });

A The variable <code>response</code> is undefined; should use <code>pm.response</code>

B The method <code>to.be.below</code> does not exist

C The test name is missing quotes

D The response time should be checked with <code>pm.response.time</code>

💡 Hint

Check the object used to access response properties in Postman scripts.

In Postman test scripts, the response object is accessed via pm.response. Using response alone causes a ReferenceError.

🧠 Conceptual

advanced

Best practice for response time assertion threshold

Which is the best reason to avoid setting a very low response time threshold (e.g., 10ms) in Postman assertions?

A Response time assertions are ignored if threshold is below 50ms

B Lower thresholds improve test accuracy and should always be used

C Postman does not support response time assertions below 100ms

D Network and server variability can cause false test failures even if the API is healthy

💡 Hint

Think about real-world network conditions and server load.

Setting too low a threshold can cause tests to fail due to normal fluctuations in network latency or server processing time, not actual problems.

❓ framework

expert

Implementing a custom response time assertion in Postman

You want to create a Postman test that fails if the response time exceeds 400ms but logs a warning if it is between 300ms and 400ms. Which script correctly implements this behavior?

A pm.test('Response time check', () => { const time = pm.response.responseTime; if (time > 400) { pm.expect.fail(`Response time too high: ${time}ms`); } else if (time > 300) { console.warn(`Warning: Response time is ${time}ms`); } else { pm.expect(time).to.be.below(300); } });

B pm.test('Response time check', () => { const time = pm.response.responseTime; if (time > 400) { console.warn(`Response time too high: ${time}ms`); } else if (time > 300) { pm.expect.fail(`Warning: Response time is ${time}ms`); } else { pm.expect(time).to.be.below(300); } });

C pm.test('Response time check', () => { const time = pm.response.responseTime; if (time > 400) { pm.expect(time).to.be.below(400); } else if (time > 300) { pm.expect(time).to.be.below(300); } });

D pm.test('Response time check', () => { const time = pm.response.responseTime; if (time > 300) { pm.expect.fail(`Response time too high: ${time}ms`); } else { pm.expect(time).to.be.below(400); } });

💡 Hint

Consider how to fail a test explicitly and how to log warnings without failing.

Option A correctly fails the test if time > 400ms using pm.expect.fail(), logs a warning if time is between 300ms and 400ms using console.warn, and passes otherwise.

Option A reverses fail and warn logic.

Option A does not log warnings and does not fail explicitly.

Option A fails for times above 300ms, which is stricter than required.