Data file integration (CSV, JSON) in Postman - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to load a CSV data file in Postman.

Postman

pm.test('Load CSV data file', function () {
    const data = pm.iterationData.[1]();
    pm.expect(data).to.not.be.undefined;
});

Drag options to blanks, or click blank then click option'

AtoString

BtoCSV

CtoObject

DtoJSON

Attempts:

3 left

💡 Hint

Common Mistakes

Using toCSV() which does not exist.

Trying to convert to string instead of JSON object.

In Postman, pm.iterationData.toJSON() converts the CSV or JSON data file row into a JSON object for easy access.

2fill in blank

medium

Complete the code to access the 'username' field from the current data row in Postman.

Postman

const username = pm.iterationData.get('[1]');

Drag options to blanks, or click blank then click option'

Auser

Busername

Cuser_name

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect field names like 'user' or 'name'.

Misspelling the field name.

The key used to access the username field must match the column header in the CSV or JSON data file, which is 'username'.

3fill in blank

hard

Fix the error in the code to correctly iterate over data rows in Postman tests.

Postman

pm.test('Check data rows', function () {
    for (let i = 0; i < pm.iterationData.[1]; i++) {
        const email = pm.iterationData.get('email');
        pm.expect(email).to.include('@');
    }
});

Drag options to blanks, or click blank then click option'

Alength

Bsize

Ccount

Dlength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() as a method instead of length property.

Using size or count which do not exist.

The pm.iterationData object has a length property to get the number of data rows. Using length() or other terms causes errors.

4fill in blank

hard

Fill both blanks to create a test that checks if the 'status' field equals 'active' for each data row.

Postman

pm.test('Status is active', function () {
    const status = pm.iterationData.get('[1]');
    pm.expect(status).to.be.[2]('active');
});

Drag options to blanks, or click blank then click option'

Astatus

Bequal

Cequals

DstatusCode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'equals' instead of 'equal' which is not a Chai method.

Using wrong field names like 'statusCode'.

The field name is 'status' and the assertion method is equal to check exact equality.

5fill in blank

hard

Fill all three blanks to create a test that verifies the 'age' field is greater than 18 for each data row.

Postman

pm.test('Age check', function () {
    const age = parseInt(pm.iterationData.get('[1]'), 10);
    pm.expect(age).to.be.[2]([3]);
});

Drag options to blanks, or click blank then click option'

Aage

Babove

C18

DgreaterThan

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'greaterThan' which is not a Chai method.

Comparing with a string instead of a number.

The field name is 'age'. The Chai assertion method to check greater than is above. The value to compare is 18.

Practice

1. What is the main purpose of using data files like CSV or JSON in Postman's Collection Runner?

easy

A. To run the same test multiple times with different input data

B. To create new APIs automatically

C. To change the Postman interface theme

D. To store test results permanently

Solution

1. Step 1: Understand data file role in Postman

   Data files provide different sets of input data for tests.

2. Step 2: Connect data files to Collection Runner

   Collection Runner uses these files to repeat tests with varied inputs.

3. Final Answer:

   To run the same test multiple times with different input data -> Option A

4. Quick Check:

   Data files = multiple test runs [OK]

Hint: Data files feed tests with many inputs [OK]

Common Mistakes:

• Thinking data files create APIs
• Confusing data files with UI settings
• Assuming data files store results

2. Which of the following is the correct way to reference a CSV data file variable named username in a Postman test script?

easy

A. pm.variables.get('username')

B. pm.data.username

C. pm.iterationData.get('username')

D. pm.request.body.username

Solution

1. Step 1: Identify how Postman accesses data file variables

   Postman uses pm.iterationData.get('variableName') to get data from CSV or JSON files.

2. Step 2: Match the correct syntax for username

   The correct method is pm.iterationData.get('username').

3. Final Answer:

   pm.iterationData.get('username') -> Option C

4. Quick Check:

   Use pm.iterationData.get() for data file variables [OK]

Hint: Use pm.iterationData.get('var') for CSV/JSON data [OK]

Common Mistakes:

• Using pm.variables.get() which accesses environment variables
• Trying to access data as object properties
• Confusing request body with data file variables

3. Given this CSV data file content:

email,password
[e-mail],pass123
[e-mail],pass456

And this test script snippet:

const email = pm.iterationData.get('email');
const password = pm.iterationData.get('password');
pm.test('Check email format', () => {
  pm.expect(email).to.include('@');
});

What will be the result of running the Collection Runner with this data file?

medium

A. Both iterations pass the test

B. Both iterations fail the test

C. First iteration passes, second fails

D. Test throws a syntax error

Solution

1. Step 1: Analyze CSV data values

   Both emails contain '@' symbol: '[e-mail]' and '[e-mail]'.

2. Step 2: Check test condition for each iteration

   The test checks if email includes '@', which is true for both rows.

3. Final Answer:

   Both iterations pass the test -> Option A

4. Quick Check:

   Email includes '@' = true for all data [OK]

Hint: Check data values against test condition carefully [OK]

Common Mistakes:

• Assuming test fails without checking data
• Confusing syntax error with logic error
• Ignoring multiple iterations in Collection Runner

4. You have a JSON data file with this content:

[
  {"user": "alice", "age": 30},
  {"user": "bob", "age": "twenty-five"}
]

When running tests that expect age to be a number, you get unexpected failures. What is the most likely cause?

medium

A. The JSON file is not properly formatted

B. The second age value is a string, not a number

C. Postman cannot read JSON files

D. The test script is missing pm.iterationData.get()

Solution

1. Step 1: Inspect JSON data values

   The first age is 30 (number), second is "twenty-five" (string).

2. Step 2: Understand test expectation

   Tests expect age to be a number, but second value is text, causing failure.

3. Final Answer:

   The second age value is a string, not a number -> Option B

4. Quick Check:

   Data type mismatch causes test failure [OK]

Hint: Check data types in JSON carefully [OK]

Common Mistakes:

• Assuming JSON format is invalid
• Blaming Postman for reading JSON
• Ignoring data type differences

5. You want to run a Postman test that uses a JSON data file with nested objects like:

[
  {"user": {"name": "John", "id": 101}, "active": true},
  {"user": {"name": "Jane", "id": 102}, "active": false}
]

Which is the correct way to access the name property inside the test script?

hard

A. pm.iterationData.get('user').get('name')

B. pm.iterationData['user']['name']

C. pm.iterationData.get('user.name')

D. pm.iterationData.get('user').name

Solution

1. Step 1: Understand how Postman accesses nested JSON data

   Postman requires getting the parent object first with pm.iterationData.get('user'), then access nested properties using JavaScript dot notation.

2. Step 2: Identify correct syntax for nested property

   Using pm.iterationData.get('user').name correctly accesses the nested name.

3. Final Answer:

   pm.iterationData.get('user').name -> Option D

4. Quick Check:

   Get parent object first, then .name [OK]

Hint: Get parent object first, then .name [OK]

Common Mistakes:

• Trying to access nested objects as JS objects directly
• Using .get() on returned object
• Using bracket notation inside pm.iterationData.get()