Running a collection in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

What is the output count after running this Postman collection?

You have a Postman collection with 3 requests. Each request returns a JSON response with a field status. The collection runs sequentially and you use a test script to count how many responses have status equal to success.

After running the collection, what is the value of the counter if the responses are: {"status": "success"}, {"status": "fail"}, {"status": "success"}?

Postman

let successCount = Number(pm.environment.get('successCount') || 0);
pm.test('Count success status', function () {
    let jsonData = pm.response.json();
    if (jsonData.status === 'success') {
        successCount++;
    }
    pm.environment.set('successCount', successCount);
});

A 1

B 2

C 0

D 3

💡 Hint

Count only responses where status is exactly success.

Only the first and third responses have status equal to success, so the count is 2.

🧠 Conceptual

intermediate

Which environment variable scope is best for sharing data across all requests in a collection run?

You want to store a variable in Postman that is accessible by all requests during a collection run but does not persist after the run ends. Which variable scope should you use?

A Global variable

B Environment variable

C Collection variable

D Local variable

💡 Hint

Think about variables that exist only during the collection run and are shared by all requests in that collection.

Collection variables exist only during the collection run and are shared by all requests in that collection. Environment and global variables persist beyond the run.

📝 Syntax

advanced

Identify the syntax error in this Postman test script snippet

What error does this Postman test script produce?

pm.test('Response has userId', () => {
  let jsonData = pm.response.json()
  pm.expect(jsonData.userId).to.eql(123);
});

A No error, script runs successfully

B TypeError: pm.expect is not a function

C SyntaxError: Missing semicolon after pm.response.json()

D ReferenceError: jsonData is not defined

💡 Hint

Check if the code syntax and function calls are correct.

The code uses arrow function syntax correctly and calls pm.expect properly. Missing semicolons are optional in JavaScript and do not cause errors here.

❓ optimization

advanced

How to optimize running a large collection with many requests?

You have a Postman collection with 100 requests. Running it sequentially takes a long time. Which approach optimizes the total run time?

A Disable tests to speed up execution

B Add delays between requests to avoid server overload

C Split the collection into smaller collections and run them one after another

D Run requests in parallel using Postman Runner's concurrency setting

💡 Hint

Think about running multiple requests at the same time.

Postman Runner allows setting concurrency to run multiple requests in parallel, reducing total run time.

🔧 Debug

expert

Why does this collection run fail to update the variable as expected?

In a collection run, you try to increment a variable counter in the test script of each request like this:

let count = pm.variables.get('counter');
count++;
pm.variables.set('counter', count);

But after the run, counter remains unchanged. Why?

A pm.variables.get() returns undefined because 'counter' is not set initially

B pm.variables.get() returns a string, so incrementing causes NaN

C pm.variables.set() updates only local variables, not environment or collection variables

D pm.variables.set() cannot update variables during collection run

💡 Hint

Check if the variable exists before incrementing.

If 'counter' is not set initially, pm.variables.get('counter') returns undefined. Incrementing undefined results in NaN, so the variable is not updated properly.