Script execution order in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Order of script execution in Postman

In Postman, when you send a request, scripts can run in different phases. Which of the following lists the correct order of script execution?

A Request Sent → Pre-request Script → Tests Script

B Pre-request Script → Request Sent → Tests Script

C Tests Script → Pre-request Script → Request Sent

D Pre-request Script → Tests Script → Request Sent

💡 Hint

Think about what needs to happen before the request is sent and what happens after.

Postman runs the Pre-request Script first to prepare or modify the request. Then it sends the request. After receiving the response, it runs the Tests Script to check the response.

❓ Predict Output

intermediate

Output of console logs in Postman scripts

Consider these Postman scripts attached to a request:

pm.test('Test 1', () => { console.log('Test script running'); });
pm.environment.set('var1', 'value1');

And the Pre-request Script:

console.log('Pre-request running');

What will be the order of console log outputs when the request is sent?

A

Pre-request running
Test script running

B

Test script running
Pre-request running

C Test script running only

D Pre-request running only

💡 Hint

Remember when each script runs relative to the request.

The Pre-request Script runs first and logs 'Pre-request running'. After the request is sent and response received, the Tests Script runs and logs 'Test script running'.

❓ assertion

advanced

Correct assertion placement in Postman scripts

You want to check if the response status code is 200. Where should you place the assertion?

A In the Pre-request Script

B In the Post-request Script

C Before sending the request

D In the Tests Script

💡 Hint

Assertions check the response after it arrives.

Assertions must be in the Tests Script because it runs after the response is received, allowing you to check response details like status code.

🔧 Debug

advanced

Debugging script execution order in Postman

You have a Pre-request Script and a Tests Script both logging messages. You notice the Tests Script logs appear before the Pre-request Script logs in the console. What is the most likely cause?

A The console is showing logs from a previous request run

B Pre-request Script runs after Tests Script by design

C There is a syntax error in the Pre-request Script stopping it from running

D Postman runs Tests Script twice before Pre-request Script

💡 Hint

Think about how console logs accumulate in Postman.

Postman console keeps logs from all requests until cleared. Seeing Tests Script logs before Pre-request logs usually means you are viewing old logs from a previous run.

❓ framework

expert

Custom script execution order in Postman Collection Runner

You run a collection with multiple requests in Postman Collection Runner. You want to run a script once before all requests and once after all requests. Where should you place these scripts?

A Use Environment Pre-request Script for before all, and Environment Tests Script for after all

B Use Pre-request Script in the first request and Tests Script in the last request

C Use Collection Pre-request Script for before all, and Collection Tests Script for after all

D Use Global Pre-request Script for before all, and Global Tests Script for after all

💡 Hint

Think about script scopes in Postman collections.

Collection-level Pre-request Script runs once before all requests in the collection, and Collection-level Tests Script runs once after all requests complete. This is the correct way to run scripts once before all and once after all requests.

Practice

1. In Postman, which script runs first when you send a request?
Collection Pre-request Script, Folder Pre-request Script, or Request Pre-request Script?

easy

A. Collection Pre-request Script

B. Folder Pre-request Script

C. Request Pre-request Script

D. Test Script

Solution

1. Step 1: Understand script types in Postman

   Pre-request scripts run before sending the request. They can be set at collection, folder, or request level.

2. Step 2: Identify execution order of pre-request scripts

   Postman runs pre-request scripts starting from the collection level, then folder, then request level.

3. Final Answer:

   Collection Pre-request Script -> Option A

4. Quick Check:

   Pre-request scripts run top-down: Collection first [OK]

Hint: Pre-request scripts run from collection to request level [OK]

Common Mistakes:

• Thinking request pre-request script runs first
• Confusing test scripts with pre-request scripts
• Assuming folder scripts run before collection scripts

2. Which of the following is the correct syntax to add a test script in Postman that checks if the response status is 200?

easy

A. test('Status is 200', () => response.status === 200);

B. pm.check('Status is 200', () => pm.response.status === 200);

C. pm.assert('Status is 200', pm.response.statusCode == 200);

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

Solution

1. Step 1: Recall Postman test script syntax

   Postman uses pm.test() with a callback function to define tests.

2. Step 2: Verify correct assertion method

   pm.response.to.have.status(200) is the correct way to check status code 200.

3. Final Answer:

   pm.test('Status is 200', function () { pm.response.to.have.status(200); }); -> Option D

4. Quick Check:

   Use pm.test() and pm.response.to.have.status() [OK]

Hint: Use pm.test() with pm.response.to.have.status() [OK]

Common Mistakes:

• Using pm.check() which does not exist
• Using test() without pm namespace
• Using pm.assert() which is invalid

3. Given these scripts in Postman:
Collection Pre-request Script: sets variable var1 = 'A'
Folder Pre-request Script: sets var1 = 'B'
Request Pre-request Script: sets var1 = 'C'
After sending the request, what is the value of var1 in the test script?

medium

A. 'C'

B. 'B'

C. Undefined

D. 'A'

Solution

1. Step 1: Understand script execution order for pre-request scripts

   Pre-request scripts run in order: collection, then folder, then request. Each can overwrite variables.

2. Step 2: Trace variable assignment

   Collection sets var1='A', folder overwrites var1='B', request overwrites var1='C'. Final value is 'C'.

3. Final Answer:

   'C' -> Option A

4. Quick Check:

   Last pre-request script sets final variable [OK]

Hint: Last pre-request script overwrites variables [OK]

Common Mistakes:

• Assuming collection script value remains
• Thinking folder script overwrites request script
• Forgetting scripts run before request

4. You wrote a test script in Postman but it never runs after sending the request. Which is the most likely reason?

medium

A. You forgot to save the request

B. The request URL is invalid

C. You placed the script in the Pre-request Script tab instead of Tests tab

D. You did not enable the collection runner

Solution

1. Step 1: Understand when test scripts run

   Test scripts run after the response is received, and must be placed in the Tests tab.

2. Step 2: Identify script placement error

   If the script is in Pre-request Script tab, it runs before sending request, not after response, so test code won't run as expected.

3. Final Answer:

   You placed the script in the Pre-request Script tab instead of Tests tab -> Option C

4. Quick Check:

   Tests run only in Tests tab after response [OK]

Hint: Put test code in Tests tab, not Pre-request tab [OK]

Common Mistakes:

• Confusing pre-request and test script tabs
• Assuming saving request affects script execution
• Thinking collection runner is needed for tests

5. You have a collection with a pre-request script setting a variable token. A folder inside the collection has a pre-request script that updates token only if it is empty. The request inside the folder has a test script that checks if token is set. Which script execution order ensures the test script sees the updated token?

hard

A. Request test script runs before folder pre-request script

B. Collection pre-request script runs first, then folder pre-request script, then request test script

C. Folder pre-request script runs before collection pre-request script

D. Request pre-request script runs after test script

Solution

1. Step 1: Recall Postman script execution order

   Pre-request scripts run in order: collection, folder, request. Test scripts run after response.

2. Step 2: Understand variable update flow

   Collection sets token, folder updates if empty, then request test script runs after response to check token.

3. Step 3: Confirm correct order

   This order ensures token is set and updated before test script checks it.

4. Final Answer:

   Collection pre-request script runs first, then folder pre-request script, then request test script -> Option B

5. Quick Check:

   Pre-request scripts run before tests in order [OK]

Hint: Pre-request scripts run before tests, top-down order [OK]

Common Mistakes:

• Thinking test scripts run before pre-request scripts
• Assuming folder scripts run before collection scripts
• Believing request pre-request scripts run after tests