Request headers in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the purpose of request headers

Which of the following best describes the main purpose of HTTP request headers in API testing?

A They carry metadata about the request such as content type, authorization, and caching policies.

B They contain the actual data payload sent to the server in the request body.

C They specify the IP address of the client making the request.

D They define the server's response format and status codes.

💡 Hint

Think about what extra information is sent along with the request but is not the main data.

Request headers provide metadata about the request, such as content type, authorization tokens, and caching instructions. They do not contain the main data payload or server response details.

❓ Predict Output

intermediate

Output of a Postman test script checking a header

Given the following Postman test script, what will be the test result if the response header Content-Type is application/json; charset=utf-8?

Postman

pm.test('Content-Type is application/json', () => {
  pm.response.to.have.header('Content-Type', 'application/json');
});

A Test fails because the header value does not exactly match 'application/json'.

B Test passes because the header contains 'application/json' as part of its value.

C Test fails because the header 'Content-Type' is missing.

D Test passes because Postman ignores charset in header value comparisons.

💡 Hint

Check if the test checks for exact match or partial match of the header value.

The test checks for an exact match of the header value 'application/json'. Since the actual header value includes charset, it does not exactly match, so the test fails.

❓ locator

advanced

Best practice for locating a header in Postman test scripts

Which of the following is the best way to check if the Authorization header exists in a Postman response?

A pm.response.headers.get('Authorization') !== undefined

B pm.response.headers['Authorization'] !== null

C pm.response.headers.find(header => header.key === 'Authorization')

D pm.response.headers.has('Authorization')

💡 Hint

Look for the method designed to check header existence directly.

The has method is the recommended way to check if a header exists in Postman response headers. Other options may cause errors or are less direct.

❓ assertion

advanced

Correct assertion for checking JSON content type header

Which Postman test assertion correctly verifies that the Content-Type header starts with application/json (ignoring charset)?

A pm.expect(pm.response.headers.get('Content-Type')).to.include('application/json');

B pm.expect(pm.response.headers.get('Content-Type')).to.match(/^application\/json/);

C pm.expect(pm.response.headers.get('Content-Type')).to.equal('application/json');

D pm.expect(pm.response.headers.get('Content-Type')).to.be.a('string');

💡 Hint

Think about how to check the start of a string with possible extra text after it.

The match assertion with a regular expression checking the start of the string is the best way to verify the header starts with 'application/json', ignoring charset or other parameters.

❓ framework

expert

Handling dynamic request headers in automated tests

In an automated API test suite using Postman, you need to send a dynamic X-Request-ID header with a unique UUID for each request. Which approach is best to implement this?

A Hardcode a fixed UUID value in the header for all requests to keep tests consistent.

B Add the UUID generation logic in the Tests script after the request is sent.

C Use a Pre-request Script to generate a UUID and set it as an environment variable, then reference it in the header value.

D Manually enter a new UUID value in the Headers tab before each test run.

💡 Hint

Consider when and where to generate dynamic data before sending the request.

Using a Pre-request Script to generate a UUID and store it in an environment variable allows the header to have a unique value each time the request runs. This is the best practice for dynamic headers.