PATCH request in Postman - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding PATCH request purpose

What is the main purpose of a PATCH request in API testing?

A To retrieve data from the server

B To delete a resource from the server

C To partially update an existing resource

D To completely replace a resource with a new one

💡 Hint

Think about updating only some fields instead of the whole object.

A PATCH request is used to partially update an existing resource, changing only specified fields without replacing the entire resource.

❓ Predict Output

intermediate

PATCH request response status code

What HTTP status code should you expect after a successful PATCH request that updates a resource?

A 201 Created

B 200 OK

C 204 No Content

D 404 Not Found

💡 Hint

Successful update usually returns a code indicating success with content.

A successful PATCH request typically returns 200 OK with the updated resource in the response body. 204 No Content is also possible but less common for PATCH.

❓ assertion

advanced

Validating PATCH request response body

You send a PATCH request to update a user's email. Which assertion best verifies the update in Postman test script?

Postman

pm.test('Email updated correctly', () => {
  const jsonData = pm.response.json();
  // Which assertion below is correct?
});

A pm.expect(jsonData.email).to.not.eql('[e-mail]');

B pm.expect(jsonData.email).to.be.undefined;

C pm.expect(pm.response.code).to.eql(404);

D pm.expect(jsonData.email).to.eql('[e-mail]');

💡 Hint

Check that the email field matches the new email you sent.

The assertion verifies that the response JSON's email field equals the updated email, confirming the PATCH worked.

🔧 Debug

advanced

Troubleshooting PATCH request failure

You send a PATCH request but receive a 400 Bad Request error. Which of these is the most likely cause?

A The request body is missing required fields or has invalid JSON format

B The server is down and not responding

C The PATCH method is not supported by the API

D The resource does not exist, so server returns 404

💡 Hint

400 errors usually mean the request data is incorrect or malformed.

A 400 Bad Request means the server could not process the request due to invalid syntax or missing required data in the PATCH body.

❓ framework

expert

Automating PATCH request tests in Postman Collection Runner

You want to automate multiple PATCH requests with different data sets in Postman Collection Runner. Which setup is best?

A Use a CSV or JSON data file with different PATCH payloads and run the collection with data iteration

B Manually edit the PATCH request body before each run

C Create separate collections for each PATCH request variation

D Use Postman monitors without data files to run PATCH requests

💡 Hint

Think about running the same test multiple times with different inputs automatically.

Using a data file with different payloads allows the Collection Runner to iterate tests automatically, making automation efficient.

Practice

1. What is the main purpose of a PATCH request in Postman?

easy

A. To update only specific fields of a resource without sending the entire data

B. To create a new resource on the server

C. To delete a resource completely

D. To retrieve data from the server

Solution

1. Step 1: Understand HTTP methods

   PATCH is used to update part of a resource, unlike POST (create) or DELETE (remove).

2. Step 2: Identify PATCH usage in Postman

   PATCH sends only the fields to update, not the whole resource.

3. Final Answer:

   To update only specific fields of a resource without sending the entire data -> Option A

4. Quick Check:

   PATCH updates part of resource = D [OK]

Hint: PATCH updates partial data, not full resource [OK]

Common Mistakes:

• Confusing PATCH with POST or PUT
• Thinking PATCH deletes data
• Assuming PATCH retrieves data

2. Which of the following is the correct way to set a PATCH request body in Postman to update the user's email?

easy

A. { "email": "[e-mail]" }

B. [ "email": "[e-mail]" ]

C. "email": "[e-mail]"

D. [e-mail]

Solution

1. Step 1: Recognize JSON format for PATCH body

   PATCH body must be valid JSON with key-value pairs inside curly braces.

2. Step 2: Check each option's syntax

   { "email": "[e-mail]" } uses correct JSON object syntax. Options A, C, D are invalid JSON or XML.

3. Final Answer:

   { "email": "[e-mail]" } -> Option A

4. Quick Check:

   Valid JSON object = B [OK]

Hint: Use JSON object with braces for PATCH body [OK]

Common Mistakes:

• Using square brackets instead of braces
• Omitting braces around JSON
• Using XML tags instead of JSON

3. Given this PATCH request in Postman to update a user's phone number:

{
  "phone": "[phone]"
}

If the server responds with status 200 and the updated user data including the new phone, what does this indicate?

medium

A. The request failed due to missing fields

B. The entire user data was replaced

C. The server ignored the PATCH request

D. The phone number was successfully updated partially

Solution

1. Step 1: Analyze PATCH request and response

   PATCH updates part of resource; status 200 means success; response shows updated data.

2. Step 2: Interpret server behavior

   Since only phone was sent and updated, server partially updated resource successfully.

3. Final Answer:

   The phone number was successfully updated partially -> Option D

4. Quick Check:

   PATCH success with 200 = partial update C [OK]

Hint: Status 200 + partial data = PATCH success [OK]

Common Mistakes:

• Assuming PATCH replaces entire resource
• Thinking 200 means failure
• Ignoring response content

4. You sent a PATCH request in Postman but received a 400 Bad Request error. Which of these is the most likely cause?

medium

A. The URL is correct but the method should be GET

B. The server does not support PATCH method

C. The request body is missing or malformed JSON

D. The response body is empty

Solution

1. Step 1: Understand 400 Bad Request meaning

   400 means client sent invalid request, often bad syntax or missing data.

2. Step 2: Check PATCH request common errors

   Malformed or missing JSON body is a frequent cause of 400 in PATCH requests.

3. Final Answer:

   The request body is missing or malformed JSON -> Option C

4. Quick Check:

   400 error = bad request body A [OK]

Hint: Check JSON body format if 400 error occurs [OK]

Common Mistakes:

• Confusing 400 with server errors
• Ignoring request body format
• Assuming method is unsupported without checking

5. You want to update a user's profile with a PATCH request in Postman. The user has fields: name, email, and address. You only want to update the address but accidentally send the entire user object with email set to null. What is the likely outcome?

hard

A. Only address updates; email remains unchanged

B. The address updates, but email becomes null on the server

C. The server rejects the request due to null email

D. The entire user profile is deleted

Solution

1. Step 1: Understand PATCH partial update behavior

   PATCH updates fields sent; if a field is sent as null, server may update it to null.

2. Step 2: Analyze sending entire object with null email

   Sending email as null means server likely sets email to null, not ignoring it.

3. Final Answer:

   The address updates, but email becomes null on the server -> Option B

4. Quick Check:

   PATCH sends null field = field updated to null A [OK]

Hint: PATCH null field updates it to null on server [OK]

Common Mistakes:

• Assuming null fields are ignored
• Thinking PATCH only updates non-null fields
• Expecting server to reject null values always