Running a collection in Postman - Build an Automation Script

Run a Postman collection and verify all requests succeed

Preconditions (2)

Step 1: Open Postman application

Step 2: Select the 'User API Tests' collection from the left sidebar

Step 3: Click the 'Run' button to open the Collection Runner

Step 4: In the Collection Runner, ensure all requests are selected

Step 5: Click the 'Start Run' button to execute the collection

Step 6: Wait for all requests to complete

Step 7: Verify that each request shows a green checkmark indicating success

✅ Expected Result: All requests in the 'User API Tests' collection run successfully with status code 200 and show green checkmarks in the Collection Runner

Automation Requirements - newman

Assertions Needed:

Verify each request response status code is 200

Verify the collection run completes without errors

Best Practices:

Use explicit checks for response status codes

Handle asynchronous execution properly

Use descriptive test names for clarity

Automated Solution

Postman

import newman from 'newman';

newman.run({
  collection: require('./User_API_Tests.postman_collection.json'),
  reporters: 'cli'
}, function (err, summary) {
  if (err) {
    console.error('Collection run encountered an error:', err);
    process.exit(1);
  }

  const failures = summary.run.failures;
  if (failures.length > 0) {
    console.error(`Test failed: ${failures.length} request(s) did not pass.`);
    failures.forEach(failure => {
      console.error(`Request: ${failure.source.name}`);
      console.error(`Error: ${failure.error.test}`);
    });
    process.exit(1);
  } else {
    console.log('All requests passed successfully.');
  }
});

This script uses Newman, the command-line tool for running Postman collections.

We import Newman and call newman.run() with the collection file path.

The reporters: 'cli' option shows results in the console.

In the callback, we check for errors running the collection.

Then we check summary.run.failures array for any failed tests.

If there are failures, we print details and exit with error code.

If no failures, we print success message.

This ensures the automation verifies all requests passed with status 200 as defined in the collection tests.

Common Mistakes - 3 Pitfalls

Not handling asynchronous callback properly

Not checking the failures array in the summary

Hardcoding collection path without relative or absolute path

Bonus Challenge

Now add data-driven testing by running the collection with 3 different environment files

Show Hint

Practice

1. What is the main purpose of Running a collection in Postman?

easy

A. To write code for APIs

B. To create new API endpoints

C. To execute a group of API requests in a specific order

D. To delete saved requests

Solution

1. Step 1: Understand what a collection is

   A collection in Postman is a group of API requests organized together.

2. Step 2: Purpose of running a collection

   Running a collection means executing all requests in that group one after another automatically.

3. Final Answer:

   To execute a group of API requests in a specific order -> Option C

4. Quick Check:

   Running a collection = executing grouped requests [OK]

Hint: Running a collection means running all requests together [OK]

Common Mistakes:

• Confusing running a collection with creating requests
• Thinking it deletes requests
• Assuming it writes code automatically

2. Which of the following is the correct way to start running a collection in Postman?

easy

A. Drag the collection to the trash bin

B. Right-click the collection and select 'Delete'

C. Open the collection and edit the request

D. Click the 'Run' button on the collection

Solution

1. Step 1: Locate the collection in Postman

   Collections appear in the sidebar with a 'Run' button visible when selected.

2. Step 2: Starting the run

   Clicking the 'Run' button starts executing all requests in the collection.

3. Final Answer:

   Click the 'Run' button on the collection -> Option D

4. Quick Check:

   Run button starts collection execution [OK]

Hint: Look for the 'Run' button to start collections [OK]

Common Mistakes:

• Choosing delete instead of run
• Editing requests does not run collection
• Dragging to trash deletes collection

3. Given a collection with 3 requests, if you run the collection and the second request fails, what happens next?

medium

A. The collection stops running immediately

B. The collection continues to run the third request

C. The collection retries the second request automatically

D. The collection deletes the failed request

Solution

1. Step 1: Understand default run behavior

   By default, Postman runs all requests in a collection sequentially regardless of individual request failures.

2. Step 2: Effect of a failed request

   A failed request does not stop the collection run; it moves on to the next request.

3. Final Answer:

   The collection continues to run the third request -> Option B

4. Quick Check:

   Collection runs all requests even if one fails [OK]

Hint: Collection runs all requests unless manually stopped [OK]

Common Mistakes:

• Assuming run stops on failure
• Thinking Postman retries automatically
• Believing failed requests get deleted

4. You try to run a collection but get an error saying 'No requests found'. What is the likely cause?

medium

A. The collection is empty with no requests inside

B. You have not selected any environment

C. Postman is offline

D. You clicked 'Run' on a single request instead of collection

Solution

1. Step 1: Analyze the error message

   'No requests found' means the collection has no requests to run.

2. Step 2: Check collection contents

   If the collection is empty, running it will cause this error.

3. Final Answer:

   The collection is empty with no requests inside -> Option A

4. Quick Check:

   Empty collection = no requests to run error [OK]

Hint: Check if collection has requests before running [OK]

Common Mistakes:

• Confusing environment selection with requests
• Assuming offline causes this error
• Thinking running single request triggers this

5. You want to run a collection multiple times with different data sets for each run. Which Postman feature helps you do this efficiently?

hard

A. Using a data file with the Collection Runner

B. Manually editing each request before running

C. Running each request separately

D. Duplicating the collection for each data set

Solution

1. Step 1: Identify the need for multiple data sets

   Running the same collection with different inputs requires data-driven testing.

2. Step 2: Use Collection Runner with data files

   Postman allows uploading CSV or JSON files to run collections multiple times with varied data.

3. Final Answer:

   Using a data file with the Collection Runner -> Option A

4. Quick Check:

   Data files + Collection Runner = multiple runs with different data [OK]

Hint: Use data files in Collection Runner for repeated tests [OK]

Common Mistakes:

• Editing requests manually wastes time
• Running requests separately is inefficient
• Duplicating collections is unnecessary