REST API testing basics in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the HTTP status code returned by this GET request?

Consider a REST API endpoint /users/123 that returns user details if the user exists. The user with ID 123 exists.

What HTTP status code should the server return for a successful GET request to /users/123?

A 404 Not Found

B 200 OK

C 500 Internal Server Error

D 201 Created

💡 Hint

Think about the standard response for a successful data retrieval.

A successful GET request returns 200 OK indicating the resource was found and returned.

❓ assertion

intermediate

Which assertion correctly verifies the JSON response contains the expected user name?

You receive this JSON response from a REST API:

{"id": 123, "name": "Alice", "email": "[e-mail]"}

Which assertion correctly checks that the name field is Alice?

A assert response.json()['name'] == 'Alice'

B assert response['name'] == 'Alice'

C assert response.json()['name'] = 'Alice'

D assert response.get('name') == 'Alice'

💡 Hint

Remember how to access JSON data from a response object.

Option A correctly calls response.json() to parse JSON and compares the name field. Option A and D are invalid because response is not a dict. Option A uses assignment = instead of comparison ==.

❓ locator

advanced

Which HTTP header is best to locate the API version in a request?

You want to test a REST API that supports multiple versions. Which HTTP header is the best practice to specify the API version in your request?

A Authorization

B Content-Type

C User-Agent

D Accept

💡 Hint

Think about which header tells the server what format or version the client expects.

The Accept header is used to specify the media type and version the client expects, e.g., application/vnd.api.v2+json. Content-Type describes the request body format, Authorization is for credentials, and User-Agent identifies the client software.

🔧 Debug

advanced

Why does this POST request test fail with a 400 Bad Request?

Test code sends this JSON payload in a POST request:

{"username": "bob", "password": 12345}

The API expects the password as a string, but the test fails with 400 Bad Request. Why?

A Password is sent as a number, but API expects a string

B Username field is missing

C POST method is not allowed on this endpoint

D JSON payload is missing required headers

💡 Hint

Check the data types in the JSON payload.

The API expects the password as a string, but the test sends it as a number (12345). This type mismatch causes the server to reject the request with 400 Bad Request.

❓ framework

expert

Which test framework feature best supports automated REST API testing with setup and teardown?

You want to write automated tests for REST APIs that require preparing test data before tests and cleaning up after. Which feature of a test framework best supports this?

A Parameterized tests

B Mocking HTTP requests

C Fixtures or setup/teardown methods

D Snapshot testing

💡 Hint

Think about how to prepare and clean test environments automatically.

Fixtures or setup/teardown methods allow you to prepare test data and environment before tests run and clean up after tests finish, which is essential for reliable REST API testing.