Status code assertion in Postman

Introduction

We check the status code to make sure the server responded correctly. It tells us if our request worked or if there was a problem.

When testing if a webpage loads successfully.

When checking if a login API returns success or failure.

When verifying that a resource was created or deleted.

When making sure an error is handled properly by the server.

Syntax

Postman

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});

The number 200 means OK or success.

You can change 200 to other codes like 404 (Not Found) or 500 (Server Error).

Examples

This checks if the server says the page or resource was not found.

Postman

pm.test("Status code is 404", function () {
    pm.response.to.have.status(404);
});

This checks if a new resource was created successfully.

Postman

pm.test("Status code is 201", function () {
    pm.response.to.have.status(201);
});

This checks if the server returned an internal error.

Postman

pm.test("Status code is 500", function () {
    pm.response.to.have.status(500);
});

Sample Program

This test checks if the server responded with status code 200, meaning success.

Postman

pm.test("Status code is 200", function () {
    pm.response.to.have.status(200);
});

Important Notes

Always check the status code before checking the response body.

Common status codes: 200 (OK), 201 (Created), 400 (Bad Request), 401 (Unauthorized), 404 (Not Found), 500 (Server Error).

Summary

Status code tells if the request worked or failed.

Use pm.response.to.have.status(code) to check it in Postman tests.

Checking status code helps catch errors early.

Practice

1. What does the status code 200 usually mean in a Postman response?

easy

A. The request was successful

B. The server could not find the requested resource

C. There was a server error

D. The request was unauthorized

Solution

1. Step 1: Understand HTTP status codes

   Status code 200 means the request was processed successfully by the server.

2. Step 2: Match code to meaning

   200 is the standard code for success, unlike 404 (not found) or 500 (server error).

3. Final Answer:

   The request was successful -> Option A

4. Quick Check:

   Status 200 = Success [OK]

Hint: 200 means success, always check for it first [OK]

Common Mistakes:

• Confusing 200 with error codes like 404 or 500
• Thinking 200 means unauthorized access
• Assuming 200 means redirect

2. Which of the following is the correct syntax to assert a status code of 404 in a Postman test script?

easy

A. pm.response.assert.status(404);

B. pm.response.to.have.status(404);

C. pm.response.status(404);

D. pm.test.status(404);

Solution

1. Step 1: Recall Postman assertion syntax

   The correct way to check status code is using pm.response.to.have.status(code).

2. Step 2: Verify each option

   Only pm.response.to.have.status(404); matches the correct syntax exactly.

3. Final Answer:

   pm.response.to.have.status(404); -> Option B

4. Quick Check:

   Use pm.response.to.have.status() [OK]

Hint: Use pm.response.to.have.status(code) for status checks [OK]

Common Mistakes:

• Omitting 'to.have' in the assertion
• Using pm.response.status() which is invalid
• Trying pm.test.status() which does not exist

3. Given this Postman test code:

pm.test('Check status', () => {
  pm.response.to.have.status(201);
});

What will be the test result if the server responds with status code 200?

medium

A. Test will pass

B. Test will be skipped

C. Test will error out

D. Test will fail

Solution

1. Step 1: Understand the assertion

   The test expects status code 201 (Created) exactly.

2. Step 2: Compare actual response code

   The server returned 200 (OK), which does not match 201, so assertion fails.

3. Final Answer:

   Test will fail -> Option D

4. Quick Check:

   Expected 201 but got 200 = Fail [OK]

Hint: Exact status code must match to pass assertion [OK]

Common Mistakes:

• Assuming 200 and 201 are interchangeable
• Thinking test errors instead of fails
• Believing test skips on mismatch

4. You wrote this Postman test:

pm.test('Status is 200', () => {
  pm.response.to.have.status = 200;
});

What is wrong with this test?

medium

A. Status code 200 is invalid

B. Missing semicolon at the end

C. Incorrect use of assignment instead of function call

D. pm.test syntax is wrong

Solution

1. Step 1: Check assertion syntax

   The code uses = which assigns a value instead of calling status(200) as a function.

2. Step 2: Identify correct usage

   The correct syntax is pm.response.to.have.status(200); to assert status code.

3. Final Answer:

   Incorrect use of assignment instead of function call -> Option C

4. Quick Check:

   Use parentheses for function calls, not assignment [OK]

Hint: Use parentheses () to call status function, not = [OK]

Common Mistakes:

• Using = instead of calling status()
• Ignoring syntax errors thinking test runs
• Confusing semicolon importance

5. You want to write a Postman test that passes only if the response status code is either 200 or 201. Which code snippet correctly asserts this?

hard

A. pm.test('Status is 200 or 201', () => {
pm.expect(pm.response.code === 200 || pm.response.code === 201).to.be.true;
});

B. pm.test('Status is 200 or 201', () => {
pm.response.to.have.status(200 || 201);
});

C. pm.test('Status is 200 or 201', () => {
pm.response.to.have.status(200) || pm.response.to.have.status(201);
});

D. pm.test('Status is 200 or 201', () => {
pm.response.to.have.status([200, 201]);
});

Solution

1. Step 1: Understand how to check multiple status codes

   Postman does not support passing multiple codes directly to status().

2. Step 2: Use logical OR with pm.expect

   pm.test('Status is 200 or 201', () => { pm.expect(pm.response.code === 200 || pm.response.code === 201).to.be.true; }); uses pm.expect with a boolean expression checking if code is 200 or 201, which is correct.

3. Final Answer:

   pm.test('Status is 200 or 201', () => { pm.expect(pm.response.code === 200 || pm.response.code === 201).to.be.true; }); -> Option A

4. Quick Check:

   Use pm.expect with OR condition for multiple codes [OK]

Hint: Use pm.expect with OR to check multiple status codes [OK]

Common Mistakes:

• Passing multiple codes directly to status()
• Using logical OR outside pm.expect
• Assuming status() accepts arrays