Tell about HTTP status codes.

HTTP status codes are standard three-digit numbers returned by the server in response to a client request. They indicate the result of the request processing.

Categories of status codes:

• 1xx (Informational): The server has received the request and is continuing the process.
• 2xx (Success): The request was successfully processed.
• 3xx (Redirection): Additional action is needed to complete the request.
• 4xx (Client Error): The request contains a syntax error or cannot be processed.
• 5xx (Server Error): The server failed to fulfill a valid request.

Common status codes:

Code	Name	Description
200	OK	The request was successfully processed.
201	Created	The resource was successfully created.
204	No Content	The request was successfully processed, but no content to return.
301	Moved Permanently	The resource has been permanently moved to a new URL.
302	Found	The resource is temporarily available at a different URL.
304	Not Modified	The resource has not been modified since the last request.
400	Bad Request	The server could not understand the request due to invalid syntax.
401	Unauthorized	Authentication is required.
403	Forbidden	Access to the resource is forbidden.
404	Not Found	The requested resource was not found.
405	Method Not Allowed	The HTTP method used is not allowed for the resource.
409	Conflict	Conflict occurred while processing the request, e.g., creating an existing resource.
422	Unprocessable Entity	The request is syntactically correct but semantically invalid.
500	Internal Server Error	Internal server error.
501	Not Implemented	The server does not support the functionality required to fulfill the request.
503	Service Unavailable	The server is temporarily unavailable.

During API testing, status codes are a key indicator of success or failure. Checking the correct status code for each request type (GET, POST, PUT, DELETE, etc.) in various scenarios (success, validation error, resource not found, authorization) is fundamental to API functional testing.

For example, creating a new resource (POST request) expects a 201 Created status, while requesting a non-existent resource (GET request) expects a 404 Not Found.

import requests

# Example of checking status code for a successful request
response = requests.get('https://jsonplaceholder.typicode.com/posts/1')
# Expect status 200 OK
assert response.status_code == 200

# Example of checking status code for a non-existent resource
response_not_found = requests.get('https://jsonplaceholder.typicode.com/posts/9999')
# Expect status 404 Not Found
assert response_not_found.status_code == 404