PCPP2 Practice Test 16 — 15 Questions

Question 1

Which THREE of the following represent types of IPC provided by the multiprocessing module?

Accepted Answer

Pipe. Multiprocessing provides Pipes, Queues, and Managers for inter-process communication.

Answer

Thread

Answer

Global

Question 2

You are using socket.socket(socket.AF_INET, socket.SOCK_DGRAM). You attempt to send 10,000 bytes via sendto(). Why might the operation raise an OSError?

Accepted Answer

The datagram size exceeds the maximum packet size allowed by the network stack.. UDP packets are limited by the MTU of the network path; trying to send a datagram larger than the buffer/MTU limits can cause an OS-level error.

Answer

The socket must be set to non-blocking mode to send large data.

Answer

UDP is connection-oriented and requires connect() first.

Answer

TCP handshaking is missing for UDP.

Question 3

Which of the following describes the difference between Process.terminate() and Process.kill()?

Accepted Answer

Terminate() sends SIGTERM, while kill() sends SIGKILL.. On most POSIX systems, terminate() sends SIGTERM (polite), while kill() sends SIGKILL (immediate).

Answer

There is no difference.

Answer

Terminate() is for threads.

Answer

Terminate() is more immediate than kill().

Answer

Kill() is only available on Windows.

Question 4

In 'unittest.mock', when you want to return a specific value based on the input arguments of a mocked function, which property should be configured?

Accepted Answer

side_effect. The 'side_effect' property allows you to assign a function that computes the return value dynamically based on arguments, unlike 'return_value' which is static.

Answer

call_args

Answer

return_value

Answer

configure_mock

Question 5

In a Python TCP server, what is the primary purpose of the backlog parameter in the listen(backlog) method?

Accepted Answer

It defines the maximum length of the queue of pending connections.. The backlog defines the maximum number of queued connections allowed before the OS starts rejecting new ones.

Answer

It sets the timeout for idle client sockets.

Answer

It limits the total number of connected clients.

Answer

It specifies the maximum number of bytes per packet.

Question 6

When implementing a custom application protocol over TCP, how should you handle message framing?

Accepted Answer

Use a unique delimiter or a length prefix header for each message.. Since TCP is a stream, you must implement a protocol layer (like length-prefixing) to know when one message ends and the next begins.

Answer

Rely on recv() returning one complete message at a time.

Answer

Call sleep() between sends to ensure packet separation.

Answer

Use UDP instead for automatic framing.

Question 7

What command-line flag is used in pytest to stop the test suite execution after the first failure?

Accepted Answer

-x. The -x (or --exitfirst) flag causes pytest to exit immediately upon the first failed test.

Answer

--stop

Answer

-f

Answer

--halt

Question 8

Which THREE of the following are valid ways to send or receive data?

Accepted Answer

socket.send(). recv(), send(), and sendall() are the primary methods for data transfer in Python sockets.

Answer

socket.transfer()

Answer

socket.push()

Question 9

You are configuring a server to handle high-concurrency requests. Why is it preferable to use the select.select() module over a simple blocking recv() loop?

Accepted Answer

It enables monitoring multiple socket descriptors for I/O readiness.. select.select() allows monitoring multiple sockets simultaneously, preventing the server from blocking on a single idle connection.

Answer

It reduces the CPU usage of the Python interpreter during idle times.

Answer

It automatically implements multi-threaded socket handling.

Answer

It automatically handles TCP flow control packets.

Question 10

You are writing a pytest plugin and need to access the command-line options. Which hook should you implement in conftest.py?

Accepted Answer

pytest_addoption. pytest_addoption is the hook used to register custom command-line options for the pytest session.

Answer

pytest_configure

Answer

pytest_runtest_setup

Answer

pytest_init

Question 11

Which TWO of the following are true regarding 'unittest' test suites?

Accepted Answer

Test classes must inherit from unittest.TestCase.. Suites can be built using TestLoader, and tests are aggregated from classes inheriting from unittest.TestCase.

Answer

Fixtures must be named 'setUp' and 'tearDown'.

Answer

You cannot run unittest from the command line.

Answer

Test suites are limited to 10 tests each.

Question 12

When handling TCP streams, why might recv(1024) return fewer than 1024 bytes even if the sender sent more?

Accepted Answer

TCP is a stream protocol; it does not guarantee message boundaries.. TCP is a stream-oriented protocol, not a message-oriented one. Data is delivered based on buffer availability and segmentation.

Answer

The packet was dropped due to network congestion.

Answer

The socket was set to non-blocking mode.

Answer

The OS limited the receive window size.

Question 13

Which THREE of the following are valid scopes for a pytest fixture?

Accepted Answer

function. The valid scopes in pytest are function, class, module, package, and session.

Answer

method

Answer

test

Question 14

You need to detect if a client has disconnected from your TCP server. What is the standard behavior of recv() when the peer performs a clean shutdown?

Accepted Answer

It returns an empty string (b'').. A clean shutdown by the peer causes recv() to return an empty bytes object (b'').

Answer

It raises a ConnectionResetError.

Answer

It returns None.

Answer

It blocks indefinitely.

Question 15

Why is the socket.socket() constructor typically called with socket.AF_INET and socket.SOCK_STREAM for a standard web server?

Accepted Answer

To provide a reliable, connection-oriented byte stream.. AF_INET defines IPv4 and SOCK_STREAM defines the TCP protocol, which are standard for HTTP.

Answer

To enable UDP broadcast.

Answer

To reduce latency for real-time video.

Answer

To support raw IP packet injection.