PCPP2 Practice Test 5 — 10 Questions

Question 1

You are refactoring a legacy module and want to use 'pytest' to check if a function raises a specific custom exception. Which construct is most idiomatic?

Accepted Answer

with pytest.raises(CustomError):. The 'pytest.raises' context manager is the standard way to verify that a block of code raises a specific exception type.

Answer

pytest.catch(CustomError)

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assert func() == CustomError

Answer

with pytest.assert_raises(CustomError):

Question 2

Which of the following is a valid way to run all tests in a directory using pytest?

Accepted Answer

pytest. Running 'pytest' without arguments in a directory defaults to discovering and executing all tests in that directory tree.

Answer

pytest --all

Answer

python -m unittest discover

Answer

pytest --execute-all

Question 3

In pytest, how can you share a fixture across multiple files?

Accepted Answer

Place it in conftest.py.. Placing the fixture in a 'conftest.py' file within a directory makes it available to all test files in that directory and subdirectories.

Answer

Define it in __init__.py.

Answer

Use the --shared-fixtures flag.

Answer

Import it in every file.

Question 4

Which of the following describes the behavior of TCP_NODELAY?

Accepted Answer

It disables Nagle's algorithm for low-latency communication.. TCP_NODELAY disables Nagle's algorithm, which otherwise buffers small packets to send them as one, reducing network overhead but increasing latency.

Answer

It forces the socket to ignore packet loss.

Answer

It enables UDP-like performance for TCP.

Answer

It increases the packet size to match MTU.

Question 5

You are writing a pytest fixture that opens a database connection. Which scope should you use to ensure the connection is created once per module, rather than once per test function?

Accepted Answer

scope='module'. The 'scope' argument in the @pytest.fixture decorator controls the lifetime. 'module' scope runs the fixture once per module.

Answer

scope='class'

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scope='function'

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scope='session'

Question 6

Which of these is the most effective way to test a function that uses 'time.sleep()' without actually waiting?

Accepted Answer

Patch 'time.sleep'.. Mocking the 'time.sleep' function prevents it from actually executing the sleep command, making tests run faster.

Answer

Use a faster machine.

Answer

Use pytest.raises.

Answer

Change the sleep duration to 0.

Question 7

You are writing a UDP server. What is the main disadvantage of using UDP for high-volume data transmission compared to TCP?

Accepted Answer

UDP does not provide delivery guarantees or ordering.. UDP provides no guarantee of delivery, order, or congestion control, requiring the application to handle these issues.

Answer

UDP packets are always larger than TCP packets.

Answer

UDP requires more handshake overhead.

Answer

UDP is not supported on all operating systems.

Question 8

Which THREE features are provided by 'pytest' but NOT by the standard 'unittest' framework?

Accepted Answer

Parametrization using markers.. pytest offers native parametrization, powerful fixture injection, and automatic test discovery without boilerplate classes.

Answer

Support for setup and teardown methods.

Answer

Basic assertion support.

Question 9

Which pytest feature allows you to run the same test multiple times with different sets of inputs?

Accepted Answer

@pytest.mark.parametrize. Parametrization using @pytest.mark.parametrize allows a test function to be executed with varying data sets.

Answer

@pytest.mark.repeat

Answer

pytest.loop()

Answer

@pytest.fixture(params=...)

Question 10

What is the significance of the SO_BROADCAST option in a UDP socket?

Accepted Answer

It enables the socket to send packets to a broadcast address.. SO_BROADCAST is a prerequisite for sending packets to the broadcast address on a network interface.

Answer

It allows the socket to handle incoming multicast traffic.

Answer

It allows the socket to listen to all ports on a machine.

Answer

It makes the socket connection-oriented.