200-901 Software Development and Design Practice Test 2 — 15 Questions

Question 1

Which THREE of the following are benefits of using event-driven architecture in a distributed system? (Choose three.)

Accepted Answer

Loose coupling between services. Event-driven architecture promotes loose coupling, scalability, and real-time responsiveness.

Answer

Eliminates the need for message brokers

Answer

Simpler debugging due to synchronous communication

Question 2

Which TWO of the following Python exception handling statements are valid? (Choose two.)

Accepted Answer

try:
    x = 1/0
except ZeroDivisionError as e:
    print(e). Options A and C are valid Python exception handling statements. Option A uses the correct `as` keyword to bind the exception instance. Option C shows proper syntax with multiple except blocks, where a generic `except:` can follow a specific except. Option B is invalid because it uses the obsolete comma syntax (`except ZeroDivisionError, e`), removed in Python 3. Option D is invalid because you cannot catch multiple exception types with a single `as` variable using a tuple; the syntax is not supported. Option E is invalid because a bare `except:` clause is considered poor practice and is not a valid 'exception handling statement' in this context—it catches all exceptions without specificity.

Answer

try:
    x = 1/0
except ZeroDivisionError, e:
    print(e)

Answer

try:
    x = 1/0
except (ZeroDivisionError, TypeError) as e:
    print(e)

Answer

try:
    x = 1/0
except:
    print('error')

Question 3

A developer is writing a Python script to iterate over a list of server hostnames. Which loop structure is most appropriate to process each hostname in the list?

Accepted Answer

for hostname in hostnames: print(hostname). The 'for item in list' loop iterates directly over each element, making it the simplest and most readable for processing each hostname.

Answer

for i, hostname in enumerate(hostnames): print(hostname)

Answer

while len(hostnames) > 0: print(hostnames.pop())

Answer

for i in range(len(hostnames)): print(hostnames[i])

Question 4

A Python script uses a dictionary to store device configuration parameters. Which key, if any, will raise a KeyError if it does not exist in the dictionary?

Accepted Answer

config['timeout']. Using square bracket notation (config['timeout']) on a dictionary will raise a KeyError if the specified key does not exist. This is a fundamental behavior of Python dictionaries: direct key access without a fallback mechanism throws an exception when the key is missing.

Answer

config.setdefault('timeout', 30)

Answer

config.get('timeout')

Answer

config.pop('timeout', None)

Question 5

When using the requests library in Python to send a POST request, which parameter should be used to send a JSON payload in the request body?

Accepted Answer

json=payload. The json= parameter automatically serializes the Python dictionary to JSON and sets the Content-Type header to application/json.

Answer

params=payload

Answer

files=payload

Answer

data=json.dumps(payload)

Question 6

A network engineer writes a Python script to handle exceptions when making REST API calls. Which exception type should be caught to handle network connectivity issues (e.g., DNS failure, refused connection)?

Accepted Answer

requests.exceptions.ConnectionError. `requests.exceptions.ConnectionError` is specifically raised when the underlying TCP connection fails, which includes scenarios like DNS resolution failures, refused connections, or the remote host being unreachable. This exception is a subclass of `RequestException` and directly maps to network-level issues at the transport layer, making it the precise exception to catch for connectivity problems.

Answer

requests.exceptions.RequestException

Answer

requests.exceptions.HTTPError

Answer

requests.exceptions.Timeout

Question 7

Given the following Python code snippet:

with open('config.json', 'r') as f:
    data = json.load(f)
print(data['interfaces'][0]['name'])

What is the expected output if config.json contains {"interfaces": [{"name": "GigabitEthernet0/1"}]}?

Accepted Answer

GigabitEthernet0/1. json.load() reads the file and returns a dict; then accessing the nested structure yields 'GigabitEthernet0/1'.

Answer

None

Answer

interfaces

Answer

Error: list indices must be integers

Question 8

A developer needs to create a Python function that accepts any number of keyword arguments and prints them. Which function definition correctly uses **kwargs?

Accepted Answer

def print_args(**kwargs): print(kwargs). The **kwargs syntax in a Python function definition collects any number of keyword arguments into a dictionary. The function then prints that dictionary, which matches the requirement to accept and print any number of keyword arguments.

Answer

def print_args(*args): print(args)

Answer

def print_args(kwargs): print(kwargs)

Answer

def print_args(*kwargs): print(kwargs)

Question 9

Which Git command is used to switch to an existing branch named 'feature-x' and update the working directory?

Accepted Answer

git checkout feature-x. `git checkout feature-x` is the traditional Git command that switches the HEAD reference to the existing branch 'feature-x' and updates the working directory to match that branch's commit history. This command performs both the branch switch and the working tree update in one operation, which is the core requirement of the question.

Answer

git merge feature-x

Answer

git branch feature-x

Answer

git switch -c feature-x

Question 10

Which HTTP status code indicates that a POST request successfully created a new resource on the server?

Accepted Answer

201 Created. The 201 Created status code is the correct response for a POST request that successfully creates a new resource. According to RFC 7231, the server should respond with 201 and include a Location header pointing to the newly created resource's URI. This is the standard behavior for RESTful APIs when a POST operation results in resource creation.

Answer

200 OK

Answer

204 No Content

Answer

202 Accepted

Question 11

In software architecture, which pattern separates an application into three interconnected components: Model (data), View (UI), and Controller (input logic)?

Accepted Answer

MVC (Model-View-Controller). The MVC pattern explicitly separates an application into three interconnected components: Model (data and business logic), View (user interface), and Controller (handles user input and updates the Model/View). This is the foundational architectural pattern for many web frameworks like Django, Ruby on Rails, and Spring MVC, where the Controller receives HTTP requests, interacts with the Model, and selects the appropriate View for rendering.

Answer

Microservices

Answer

Event-driven

Answer

REST

Question 12

Given the Python list comprehension: result = [x*2 for x in range(10) if x > 5]
What is the value of result?

Accepted Answer

[12, 14, 16, 18]. The list comprehension `[x*2 for x in range(10) if x > 5]` iterates over `x` from 0 to 9, filters to only include `x` values greater than 5 (i.e., 6, 7, 8, 9), and multiplies each by 2, producing `[12, 14, 16, 18]`. This is a standard Python comprehension with a conditional filter.

Answer

[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]

Answer

[10, 12, 14, 16, 18]

Answer

[6, 7, 8, 9]

Question 13

A Python script uses a try/except block to handle API errors. If the API returns a 429 status code, which mechanism should the script implement to handle the error appropriately?

Accepted Answer

Wait for the time specified in the Retry-After header and then retry. A 429 status code indicates the client has sent too many requests in a given amount of time (rate limiting). The HTTP specification (RFC 6585) recommends including a Retry-After header in the response, which tells the client how long to wait before retrying. Implementing a wait based on this header and then retrying is the correct and respectful way to handle rate limiting, allowing the script to eventually succeed without overwhelming the server.

Answer

Switch to a different API endpoint

Answer

Log the error and continue without retrying

Answer

Immediately retry the same request without delay

Question 14

In a microservices architecture, which of the following is a primary advantage over a monolithic architecture?

Accepted Answer

Independent deployability and scaling of services. Microservices allow independent deployment and scaling of services, which is a key advantage.

Answer

Easier end-to-end testing

Answer

Lower operational overhead

Answer

Simpler inter-service communication

Question 15

Which TWO of the following are valid Python data types?

Accepted Answer

list. List and set are both built-in Python data types. List is an ordered, mutable collection, while set is an unordered collection of unique elements. Array is not a built-in data type; it is provided by the array module. Dict is also a built-in data type, but the question requires selecting exactly two options, and list and set are the correct ones. Map is a built-in function, not a data type.

Answer

array

Answer

dict

Answer

map