200-901 Software Development and Design Practice Test 3 — 15 Questions

Question 1

Which TWO HTTP status codes indicate client errors?

Accepted Answer

404 Not Found. 400 Bad Request and 404 Not Found are both client error statuses (4xx).

Answer

500 Internal Server Error

Answer

200 OK

Answer

201 Created

Question 2

Which THREE statements about RESTful APIs are true?

Accepted Answer

They use HTTP methods to perform CRUD operations.. RESTful APIs use standard HTTP methods (GET, POST, PUT, PATCH, DELETE) to map directly to CRUD (Create, Read, Update, Delete) operations. For example, POST creates a resource, GET retrieves it, PUT/PATCH updates it, and DELETE removes it, aligning with the REST architectural constraint of uniform interface.

Answer

They require WebSockets for communication.

Answer

They use SOAP as the message format.

Question 3

A Python script uses the 'requests' library to make a POST request to create a new resource. Which HTTP status code indicates successful creation?

Accepted Answer

201 Created. According to the REST API conventions, a successful POST request returns status code 201 Created.

Answer

204 No Content

Answer

200 OK

Answer

301 Moved Permanently

Question 4

A developer needs to read a JSON configuration file and parse it into a Python dictionary. The file contains nested objects. Which code snippet correctly accomplishes this?

Accepted Answer

with open('config.json', 'r') as f: data = json.load(f). The correct approach is to open the file with a context manager and use json.load() with the file object to parse the JSON directly into a Python dictionary. json.loads() is for parsing a JSON string, not a file object.

Answer

with open('config.json', 'r') as f: data = json.loads(f)

Answer

data = json.loads(open('config.json', 'r').read())

Answer

with open('config.json', 'r') as f: data = json.dumps(f.read())

Question 5

An automation engineer is writing a Python script to interact with a REST API that requires authentication. The API returns a 403 Forbidden status. Which scenario best explains this response?

Accepted Answer

The authentication token is invalid, and the request is not allowed.. A 403 Forbidden status code indicates that the server understood the request but refuses to authorize it. In the context of a REST API that requires authentication, a 403 is typically returned when the client is authenticated but lacks sufficient permissions to access the resource. It can also be returned for invalid or expired tokens when the server can identify the user and explicitly denies access without offering a challenge (unlike 401, which includes a WWW-Authenticate header to prompt for credentials). A missing token, however, results in a 401 Unauthorized, as the client has not provided any authentication.

Answer

The request was malformed and the server cannot process it.

Answer

The requested resource does not exist on the server.

Answer

The server is temporarily unavailable due to maintenance.

Question 6

A developer is implementing a Python function that makes an HTTP GET request to an API and returns the response time. Which code snippet correctly measures the elapsed time?

Accepted Answer

import time; start = time.time(); response = requests.get(url); return time.time() - start. Using time.time() before and after the request and subtracting gives the elapsed time in seconds.

Answer

response = requests.get(url); return response.headers['Date']

Answer

response = requests.get(url); return response.elapsed.total_seconds()

Answer

start = time.time(); response = requests.get(url); return time.time() - start

Question 7

Which data structure in Python would be most appropriate for storing a collection of unique items and performing fast membership tests?

Accepted Answer

Set. A set is the correct choice because it is implemented as a hash table in Python, which provides O(1) average-time complexity for membership tests using the `in` operator. Sets automatically enforce uniqueness, meaning duplicate items are not allowed, making them ideal for storing a collection of distinct elements. This directly matches the requirement for fast membership testing and uniqueness.

Answer

Tuple

Answer

List

Answer

Dictionary

Question 8

A developer needs to update an existing resource via a REST API. The update should be partial, meaning only the fields provided in the request body should be changed. Which HTTP method should be used?

Accepted Answer

PATCH. PATCH is used for partial updates to a resource, while PUT replaces the entire resource.

Answer

DELETE

Answer

PUT

Answer

POST

Question 9

A developer is writing a Python script that processes a large CSV file. The script uses 'with open(file, 'r') as f' to read the file. Why is this approach preferred over calling f = open(file) and then f.close()?

Accepted Answer

It automatically closes the file when the block exits, even if an exception is raised.. The 'with' statement in Python implements a context manager that automatically calls the file object's __exit__ method when the block exits, ensuring the file is closed even if an exception occurs. This prevents resource leaks and is the recommended pattern for file I/O in Python, as explicitly calling f.close() may be skipped if an exception is raised before the close call.

Answer

It allows the file to be opened in both read and write mode simultaneously.

Answer

It reduces memory usage by loading the file in chunks.

Answer

It increases the speed of file operations.

Question 10

Which Git command is used to create a new branch and switch to it in one step?

Accepted Answer

git checkout -b . The 'git checkout -b ' command creates a new branch and switches to it immediately.

Answer

git branch <branch>

Answer

git branch -d

Answer

git checkout

Question 11

In Python, which of the following is a valid way to define a function that accepts a variable number of positional arguments?

Accepted Answer

def func(*args):. In Python, the `*args` syntax in a function definition allows the function to accept a variable number of positional arguments. The asterisk (`*`) collects all extra positional arguments into a tuple named `args`, enabling flexible argument handling.

Answer

def func(args):

Answer

def func(args*):

Answer

def func(**kwargs):

Question 12

A developer is designing a microservices architecture for a network monitoring application. Which of the following is a key advantage of microservices over a monolithic architecture?

Accepted Answer

Independent deployability and scalability of services. Microservices architecture enables each service to be deployed, updated, and scaled independently without affecting other services. This is a key advantage over monolithic architectures, where any change requires rebuilding and redeploying the entire application. For a network monitoring application, independent scalability allows resource-intensive services (e.g., packet capture) to scale separately from lightweight services (e.g., alerting).

Answer

Lower latency due to in-process communication

Answer

Easier to maintain as a single codebase

Answer

Simpler inter-service communication

Question 13

A Python script uses a list comprehension: [x**2 for x in range(20) if x % 2 == 0]. Which of the following is equivalent?

Accepted Answer

result = [] 
for x in range(20): 
    if x % 2 == 0: 
        result.append(x**2). It directly translates the list comprehension into an equivalent for-loop with a conditional append. The comprehension `[x**2 for x in range(20) if x % 2 == 0]` iterates over numbers 0–19, filters for even numbers (x % 2 == 0), squares each, and collects the results in a list. Option A's explicit loop and conditional produce the exact same sequence of appended values.

Answer

result = map(lambda x: x**2, filter(lambda x: x % 2 == 0, range(20)))

Answer

result = [] 
for x in range(20): 
    result.append(x**2)

Answer

result = [x**2 for x in range(20) if x % 2 != 0]

Question 14

In the context of REST API design, which HTTP status code should be returned when a client sends a request that exceeds the API rate limit?

Accepted Answer

429 Too Many Requests. (429 Too Many Requests) is correct because RFC 6585 defines this status code specifically for cases where a client has sent too many requests in a given time frame, exceeding the API's rate limit. REST APIs use this response to enforce throttling and inform the client to back off, often including a Retry-After header to indicate when to retry.

Answer

503 Service Unavailable

Answer

400 Bad Request

Answer

401 Unauthorized

Question 15

A DevOps engineer is managing a Git repository and wants to discard local changes to a file and revert it to the last committed state. Which TWO commands can accomplish this? (Choose two.)

Accepted Answer

git checkout -- . Both `git checkout -- ` and `git restore ` discard unstaged local changes to a file, reverting it to the content of the last commit (HEAD). `git checkout -- ` is the traditional command, while `git restore ` is the newer, more intuitive alternative introduced in Git 2.23. Both operate on the working tree without affecting the staging area or commit history.

Answer

git reset --hard HEAD

Answer

git stash drop

Answer

git revert <file>