Iteration count in Postman - Build an Automation Script

Verify iteration count in Postman collection runner

Preconditions (2)

Step 1: Open the Postman collection runner

Step 2: Select the collection to run

Step 3: Set the iteration count to 3

Step 4: Start the run

Step 5: Observe the number of times the request is sent

✅ Expected Result: The request is executed exactly 3 times as per the iteration count set

Automation Requirements - Postman test scripts

Assertions Needed:

Verify that the current iteration number is less than the total iteration count

Verify that the request is executed the expected number of times

Best Practices:

Use pm.info.iteration to get the current iteration number

Use pm.test to write assertions

Keep test scripts simple and clear

Automated Solution

Postman

pm.test('Iteration count is within expected range', function () {
    pm.expect(pm.info.iteration).to.be.below(3);
});

This test script uses pm.info.iteration to get the current iteration number, which starts from 0. The assertion checks that the iteration number is less than 3, meaning the test runs exactly 3 times (0, 1, 2). This confirms the iteration count is respected during the collection run.

Using pm.test defines a test with a clear name, and pm.expect is used for assertion following Postman best practices.

Common Mistakes - 3 Pitfalls

Using pm.info.iteration without considering zero-based index

Not setting iteration count in collection runner before running tests

Writing complex logic inside test scripts to count iterations

Bonus Challenge

Now add data-driven testing with 3 different data sets and verify iteration count for each

Show Hint

Practice

1. What does the iterationCount setting in Postman control?

easy

A. The number of requests in a collection

B. The number of times a collection or request runs automatically

C. The number of tests inside a single request

D. The number of environments available

Solution

1. Step 1: Understand the role of iterationCount

   The iterationCount defines how many times Postman runs the entire collection or request automatically.

2. Step 2: Differentiate from other counts

   It is not about the number of requests or tests, but how many times the run repeats.

3. Final Answer:

   The number of times a collection or request runs automatically -> Option B

4. Quick Check:

   iterationCount = run times [OK]

Hint: iterationCount means how many times to run tests [OK]

Common Mistakes:

• Confusing iterationCount with number of requests
• Thinking iterationCount counts tests inside a request
• Mixing iterationCount with environment count

2. Which of the following is the correct way to set iteration count to 5 in Postman Collection Runner?

easy

A. Set iterationCount = 5 in the pre-request script

B. Set environment variable iterationCount to 5

C. Add pm.iterationCount = 5 in the test script

D. Enter 5 in the 'Iterations' field of the Collection Runner UI

Solution

1. Step 1: Identify how to set iteration count in Postman UI

   The Collection Runner has an 'Iterations' input field where you specify how many times to run.

2. Step 2: Understand script limitations

   Setting iterationCount in scripts or environment variables does not control the runner's iteration count.

3. Final Answer:

   Enter 5 in the 'Iterations' field of the Collection Runner UI -> Option D

4. Quick Check:

   Use Collection Runner UI to set iterations [OK]

Hint: Set iterations number in Collection Runner UI field [OK]

Common Mistakes:

• Trying to set iterationCount in scripts
• Confusing environment variables with runner settings
• Assuming iterationCount is a pm API property

3. Consider this test script in Postman run with iterationCount = 3:

console.log(pm.info.iteration);
pm.test('Check iteration', () => {
  pm.expect(pm.info.iteration).to.be.below(3);
});

What will be the console output and test result for each iteration?

medium

A. Console logs 0,1,2; last test fails

B. Console logs 1,2,3; last test fails

C. Console logs 0,1,2; all tests pass

D. Console logs 1,2,3; all tests pass

Solution

1. Step 1: Understand pm.info.iteration values

   Iteration count starts at 0, so for 3 iterations, values are 0, 1, 2.

2. Step 2: Check test condition pm.expect(pm.info.iteration).to.be.below(3)

   All iteration values (0,1,2) are less than 3, so all tests pass.

3. Final Answer:

   Console logs 0,1,2; all tests pass -> Option C

4. Quick Check:

   Iteration index starts at 0 and is below count [OK]

Hint: Iteration index starts at 0, less than iterationCount [OK]

Common Mistakes:

• Assuming iteration starts at 1
• Expecting iteration to equal iterationCount
• Confusing iterationCount with max iteration index

4. You wrote this pre-request script to stop running after 3 iterations:

if (pm.info.iterationCount > 3) {
  postman.setNextRequest(null);
}

Why does the collection keep running beyond 3 iterations?

medium

A. pm.info.iterationCount is total iterations, not current iteration index

B. postman.setNextRequest(null) does not stop iterations

C. pm.info.iterationCount is read-only and cannot be used in conditions

D. The script syntax is incorrect and causes error

Solution

1. Step 1: Understand pm.info.iterationCount meaning

   pm.info.iterationCount is the total number of iterations set, not the current iteration number.

2. Step 2: Identify correct property for current iteration

   The current iteration index is pm.info.iteration, which starts at 0.

3. Final Answer:

   pm.info.iterationCount is total iterations, not current iteration index -> Option A

4. Quick Check:

   Use pm.info.iteration to check current iteration [OK]

Hint: Use pm.info.iteration for current run, not iterationCount [OK]

Common Mistakes:

• Confusing iterationCount with iteration index
• Expecting setNextRequest(null) to stop all iterations
• Using wrong property names in conditions

5. You want to run a Postman collection 4 times, but skip iteration 2 (zero-based). Which script in the pre-request script will achieve this?

hard

A. if (pm.info.iteration === 2) { postman.setNextRequest(null); }

B. if (pm.info.iteration === 2) { postman.setNextRequest(pm.info.requestName); }

C. if (pm.info.iteration === 2) { postman.setNextRequest('Request1'); }

D. if (pm.info.iteration === 2) { postman.setNextRequest('Request3'); }

Solution

1. Step 1: Identify how to skip an iteration

   To skip iteration 2, we stop the run at that iteration by setting next request to null.

2. Step 2: Use correct condition and method

   Check if current iteration is 2, then call postman.setNextRequest(null) to stop further requests in that iteration.

3. Final Answer:

   if (pm.info.iteration === 2) { postman.setNextRequest(null); } -> Option A

4. Quick Check:

   Set next request null to skip iteration [OK]

Hint: Use setNextRequest(null) on iteration to skip it [OK]

Common Mistakes:

• Setting next request to current or wrong request name
• Confusing iteration index with iterationCount
• Not stopping requests properly to skip iteration