API versioning validation in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is API versioning?

API versioning is a way to manage changes in an API by assigning different versions. This helps clients use the API without breaking when updates happen.

beginner

Why is API versioning validation important?

It ensures that the API responds correctly to requests for different versions, preventing errors and maintaining compatibility for users.

beginner

Name two common ways to specify API versions in requests.

1. In the URL path (e.g., /v1/resource) 2. In request headers (e.g., Accept: application/vnd.example.v1+json)

beginner

How can Postman help in API versioning validation?

Postman can send requests with different version identifiers and check if the responses match expected versions, helping catch versioning issues early.

beginner

What is a good test assertion for API versioning validation in Postman?

Check the response status is 200 and the version field in the response body matches the requested version.

Which of these is NOT a common way to specify API version?

A In the response time

B In the request header

C In the query parameters

D In the URL path

Response time is unrelated to API versioning. Versions are usually in URL, headers, or query parameters.

What status code usually indicates a successful API version request?

A 404

B 500

C 200

D 301

Status code 200 means the request was successful.

In Postman, where do you write code to check API version in the response?

A Pre-request Script

B Tests tab

C Body tab

D Headers tab

The Tests tab is used to write assertions to validate responses.

If an API version is missing or unsupported, what is a good response status?

A 426 Upgrade Required

B 200 OK

C 404 Not Found

D 400 Bad Request

426 Upgrade Required tells the client to use a different API version.

Which header might be used to specify API version?

A User-Agent

B Content-Type

C Authorization

D Accept

The Accept header can specify the API version using media type versioning.

Explain how you would validate API versioning using Postman.

Think about sending requests and writing tests in Postman.

List common methods to specify API versions and why versioning matters.

Consider how clients tell the server which API version to use.

Practice

1. What is the main purpose of API versioning validation in Postman?

easy

A. To test the API authentication method

B. To check if the API URL is reachable

C. To verify the API response time

D. To ensure the API response uses the correct version

Solution

1. Step 1: Understand API versioning validation

   API versioning validation checks if the API response matches the expected version.

2. Step 2: Identify the main goal in Postman

   In Postman, this means verifying the version value in the response body or headers.

3. Final Answer:

   To ensure the API response uses the correct version -> Option D

4. Quick Check:

   API version check = Correct version [OK]

Hint: Focus on version correctness in API response [OK]

Common Mistakes:

• Confusing version check with response time
• Checking URL reachability instead of version
• Testing authentication instead of version

2. Which Postman test script correctly asserts that the API version in the response header is 'v2'?

easy

A. pm.response.headers.get('api-version').to.eql('v2');

B. pm.expect(pm.response.headers.get('api-version')).to.eql('v2');

C. pm.expect(pm.response.body.apiVersion).to.eql('v2');

D. pm.expect(pm.response.headers['api-version']).to.equal('v2');

Solution

1. Step 1: Check correct method to get header value

   Use pm.response.headers.get('header-name') to get header value in Postman.

2. Step 2: Use pm.expect() with .to.eql() for assertion

   pm.expect(...).to.eql('v2') correctly asserts the value equals 'v2'.

3. Final Answer:

   pm.expect(pm.response.headers.get('api-version')).to.eql('v2'); -> Option B

4. Quick Check:

   Use headers.get() + pm.expect() [OK]

Hint: Use headers.get() with pm.expect().to.eql() for header checks [OK]

Common Mistakes:

• Using pm.response.headers['api-version'] which is undefined
• Calling to.eql() directly on header getter without pm.expect()
• Checking version in body when question asks for header

3. Given this Postman test script, what will be the test result if the response JSON is {"version": "1.0"}?

pm.test('Check API version', () => {
  pm.expect(pm.response.json().version).to.equal('2.0');
});

medium

A. Test throws syntax error

B. Test passes because version key exists

C. Test fails because version is '1.0', not '2.0'

D. Test passes because .to.equal() ignores value

Solution

1. Step 1: Understand the test assertion

   The test expects the version value to be exactly '2.0'.

2. Step 2: Compare actual response version with expected

   The response has version '1.0', which does not equal '2.0', so assertion fails.

3. Final Answer:

   Test fails because version is '1.0', not '2.0' -> Option C

4. Quick Check:

   Expected '2.0' vs actual '1.0' = Fail [OK]

Hint: Match expected version exactly to pass test [OK]

Common Mistakes:

• Assuming test passes if key exists
• Thinking .to.equal() ignores value differences
• Confusing syntax error with assertion failure

4. You wrote this Postman test to check API version in response header:

pm.test('API version is v1', () => {
  pm.expect(pm.response.headers['api-version']).to.eql('v1');
});

But the test always fails. What is the likely issue?

medium

A. pm.response.headers is not an object with keys, use .get() method instead

B. The header name should be capitalized as 'Api-Version'

C. The assertion method should be .to.equal() not .to.eql()

D. pm.expect() cannot be used for header validation

Solution

1. Step 1: Understand how to access headers in Postman

   pm.response.headers is a special object; headers must be accessed with .get('header-name').

2. Step 2: Identify the error in header access

   Using pm.response.headers['api-version'] returns undefined, causing assertion failure.

3. Final Answer:

   pm.response.headers is not an object with keys, use .get() method instead -> Option A

4. Quick Check:

   Use headers.get() to access headers [OK]

Hint: Use headers.get('name') to access headers in Postman [OK]

Common Mistakes:

• Accessing headers like a normal object
• Changing header name case unnecessarily
• Confusing .to.eql() with .to.equal() causing failure

5. You want to validate that your API supports multiple versions: 'v1', 'v2', or 'v3'. Which Postman test script correctly checks the response header 'api-version' against these allowed versions?

hard

A. pm.test('API version is valid', () => {
const version = pm.response.headers.get('api-version');
pm.expect(version).to.be.oneOf(['v1', 'v2', 'v3']);
});

B. pm.test('API version is valid', () => {
const version = pm.response.headers.get('api-version');
pm.expect(version === 'v1' || 'v2' || 'v3').to.be.true;
});

C. pm.test('API version is valid', () => {
const version = pm.response.headers.get('api-version');
pm.expect(version).to.include(['v1', 'v2', 'v3']);
});

D. pm.test('API version is valid', () => {
const version = pm.response.headers.get('api-version');
pm.expect(version).to.eql('v1' || 'v2' || 'v3');
});

Solution

1. Step 1: Understand how to check multiple allowed values

   pm.expect(...).to.be.oneOf(array) checks if value is in the array.

2. Step 2: Analyze each option's correctness

   pm.test('API version is valid', () => { const version = pm.response.headers.get('api-version'); pm.expect(version).to.be.oneOf(['v1', 'v2', 'v3']); }); uses .to.be.oneOf(['v1','v2','v3']) correctly. pm.test('API version is valid', () => { const version = pm.response.headers.get('api-version'); pm.expect(version).to.include(['v1', 'v2', 'v3']); }); uses .to.include(array) which is invalid. pm.test('API version is valid', () => { const version = pm.response.headers.get('api-version'); pm.expect(version === 'v1' || 'v2' || 'v3').to.be.true; }); uses incorrect boolean logic. pm.test('API version is valid', () => { const version = pm.response.headers.get('api-version'); pm.expect(version).to.eql('v1' || 'v2' || 'v3'); }); uses .to.eql() with || which evaluates incorrectly.

3. Final Answer:

   pm.expect(version).to.be.oneOf(['v1', 'v2', 'v3']); -> Option A

4. Quick Check:

   Use .to.be.oneOf() for multiple allowed values [OK]

Hint: Use .to.be.oneOf() to check multiple valid versions [OK]

Common Mistakes:

• Using .to.include() incorrectly on array
• Writing boolean OR logic inside pm.expect()
• Using .to.eql() with OR operator causing wrong check