PCAP Modules and Packages Practice Test 6 — 15 Questions

Question 1

Drag and drop the steps to perform unit testing with the unittest framework in Python into the correct order.

Accepted Answer

Import unittest, then create a TestCase subclass, then define test methods (starting with 'test_'), then call unittest.main(). Unit testing with unittest requires importing, creating a TestCase subclass, writing test methods, and calling unittest.main().

Answer

Create a TestCase subclass, then import unittest, then define test methods, then call unittest.main()

Answer

Import unittest, then define test methods, then create a TestCase subclass, then call unittest.main()

Answer

Import unittest, then create a TestCase subclass, then call unittest.main(), then define test methods

Question 2

During development, a programmer modifies a module that is already imported in the current Python session. To see the changes without restarting the interpreter, which function from the importlib module should be called?

Accepted Answer

importlib.reload(). `importlib.reload()` is the official Python function to re-import a previously imported module, applying any changes made to its source code without restarting the interpreter. It is part of the `importlib` module and is the recommended way to reload modules in Python 3.

Answer

reload()

Answer

reload_module()

Answer

importlib.import_module()

Question 3

Given package structure: pack/__init__.py, pack/subpack/__init__.py, pack/subpack/mod.py. Inside pack/__init__.py, which import statement correctly imports mod.py using a relative import?

Accepted Answer

from .subpack import mod. `from .subpack import mod` uses a leading dot to indicate a relative import from the current package (`pack`), then navigates into `subpack` and imports `mod`. This is the proper syntax for importing a module from a subpackage within the same parent package.

Answer

from . import subpack.mod

Answer

from subpack import mod

Answer

from ..subpack import mod

Question 4

A Python script fails with 'ModuleNotFoundError: No module named 'myapp.config''. The environment variable PYTHONPATH is not set. Which of the following is the most likely cause?

Accepted Answer

The module is located in a directory not included in sys.path. When PYTHONPATH is not set, Python relies solely on sys.path to locate modules. sys.path includes the script's directory, standard library paths, and site-packages. If 'myapp.config' is not in any of these directories, Python raises ModuleNotFoundError. Option A correctly identifies that the module is in a directory not included in sys.path.

Answer

The module's __init__.py is missing

Answer

The module is installed in a different Python version's site-packages

Answer

The module has a syntax error

Question 5

Which of the following statements about the __init__.py file in a package is true?

Accepted Answer

It is required for a directory to be considered a regular package. In Python, a directory containing an `__init__.py` file is recognized as a regular package. This file can be empty or contain initialization code, and its presence is required for the directory to be imported as a package (as opposed to a namespace package). Without it, Python will not treat the directory as a regular package.

Answer

It is required for a namespace package

Answer

It cannot contain executable code

Answer

It is automatically generated by Python

Question 6

A team is developing a large application and wants to organize code into packages. Which of the following is a best practice for package design?

Accepted Answer

Use absolute imports with the package name to prevent breakage when the package is moved. Using absolute imports with the full package name (e.g., `from package.module import something`) ensures that the import path is explicit and independent of the module's location within the package. This prevents breakage when the package is moved or installed in a different location, as the import references the top-level package name rather than a relative path that may change. Absolute imports are the recommended style in PEP 8 for clarity and maintainability in larger applications.

Answer

Use relative imports inside the package to avoid hardcoding the package name

Answer

Keep all modules in a single package for simplicity

Answer

Avoid using __init__.py to keep packages lightweight

Question 7

A developer runs 'pip install mypackage' but gets a 'PermissionError'. Which command should be used to install the package for the current user only?

Accepted Answer

pip install --user mypackage. The `--user` flag instructs pip to install the package into the user's site-packages directory (e.g., `~/.local/lib/pythonX.Y/site-packages` on Unix), which does not require elevated permissions. This avoids the `PermissionError` that occurs when pip tries to write to the system-wide site-packages directory (e.g., `/usr/lib/python3/dist-packages`) without administrator privileges.

Answer

sudo pip install mypackage

Answer

pip install --ignore-installed mypackage

Answer

pip install --target mypackage

Question 8

Which of the following is a valid way to import a module named 'math' and assign it an alias 'm'?

Accepted Answer

import math as m. Python's `import` statement allows you to import a module and assign it an alias using the `as` keyword, as in `import math as m`. This creates a reference to the `math` module under the name `m`, so you can call functions like `m.sqrt(16)` without polluting the namespace with the original module name.

Answer

alias math as m

Answer

from math import * as m

Answer

import m from math

Question 9

Refer to the exhibit. A script executes 'from mypackage import *'. Which functions are available in the global namespace?

Accepted Answer

None, because __all__ lists modules, not functions. When `from mypackage import *` is executed, Python looks for the `__all__` list in the package's `__init__.py` file. In this exhibit, `__all__` is defined as `['module_a', 'module_b']`, which are module names, not function names. The `import *` statement imports the modules listed in `__all__` into the global namespace, not their individual functions. Therefore, `func` from either module is not directly available; you would need to reference them as `module_a.func` or `module_b.func`.

Answer

Only func from module_a

Answer

It raises an ImportError because __all__ should contain function names

Answer

func from both module_a and module_b

Question 10

Refer to the exhibit. Given the project structure, which of the following import statements in main.py would cause an ImportError?

Accepted Answer

from ..utils import helpers. Uses a relative import with '..' which is only valid inside a package (i.e., when the module is loaded as part of a package and has a __package__ attribute set). In a flat project structure where main.py is a top-level script, '..' attempts to go above the top-level package, which is not allowed and raises an ImportError. Python's import system requires that relative imports be used only within a package hierarchy.

Answer

from utils import strings

Answer

from utils import helpers

Answer

from utils.strings import format

Question 11

A Python script uses a third-party library 'requests'. The developer wants to ensure that the exact version 2.25.1 is installed in the project's environment. Which tool and command should be used?

Accepted Answer

pip install requests==2.25.1. Both options B and C are correct because they use the standard pip syntax for pinning a specific version: `package==version`. The command `pip install requests==2.25.1` (B) works on systems where `pip` is linked to Python 3, while `pip3 install requests==2.25.1` (C) explicitly invokes the Python 3 version of pip. Both achieve the same result—installing requests exactly version 2.25.1. Option A fails to specify a version, and option D contains a typo ('instll') that will fail.

Answer

pip install requests

Answer

pip instll requests==2.25.1

Question 12

A team is using a shared Python environment where multiple projects have conflicting dependencies. Which approach is the best practice to isolate project dependencies?

Accepted Answer

Create a virtual environment using 'python -m venv' and install dependencies inside it.. Using `python -m venv` creates an isolated virtual environment with its own `site-packages` directory, preventing dependency conflicts between projects. This is the standard best practice recommended by the Python Packaging Authority (PyPA) for managing project-specific dependencies without affecting the system-wide Python installation.

Answer

Manually modify sys.path in each script to include different package directories.

Answer

Install all dependencies in the system-wide site-packages directory.

Answer

Install all packages using 'pip install --user' to avoid system conflicts.

Question 13

Which TWO of the following are valid ways to import a function 'foo' from a module 'bar' that is located in a package 'mypackage'?

Accepted Answer

from mypackage.bar import foo. The syntax `from mypackage.bar import foo` directly imports the function `foo` from the module `bar` within the package `mypackage`. This is the standard Python import statement for importing a specific attribute from a submodule.

Answer

from mypackage import bar.foo

Answer

from . import bar.foo

Answer

import mypackage.bar.foo

Question 14

Which THREE of the following statements about Python's module search path are true?

Accepted Answer

The PYTHONPATH environment variable can be used to add custom directories to sys.path.. The PYTHONPATH environment variable is a standard mechanism for extending Python's module search path. When Python starts, it reads the PYTHONPATH variable and prepends its contents to sys.path, allowing users to specify additional directories where Python should look for modules before falling back to the default search order.

Answer

The site-packages directory is searched before the PYTHONPATH directories.

Answer

The current working directory is always the last entry in sys.path.

Question 15

A Python script placed in /opt/myapp/script.py fails with ImportError when run from a cron job with the command: python /opt/myapp/script.py. The script works when run manually from the /opt/myapp/ directory. The script contains the line: from . import config. The config module is located in /opt/myapp/lib/config.py with an __init__.py in /opt/myapp/lib/. What is the most likely cause of the failure?

Accepted Answer

Relative imports are not allowed in a script that is executed directly because its __name__ is not set to a package name.. When a Python script is executed directly (e.g., `python /opt/myapp/script.py`), its `__name__` is set to `'__main__'`, not to a package name. Relative imports (like `from . import config`) require the importing module to be part of a package with a proper `__name__` reflecting the package hierarchy. Since the script is run as the top-level entry point, the relative import fails with an `ImportError`. This explains why the script works when run manually from `/opt/myapp/` (if the working directory is set appropriately, but the relative import still fails unless the script is run as a module with `-m`), but fails from cron where the working directory is typically the user's home directory.

Answer

The __init__.py file in the lib directory is empty and should contain imports.

Answer

The lib directory is not in sys.path when the script is run from cron.

Answer

The cron job uses a different Python interpreter that does not have the required standard library.