PCPP2 Software Testing — 25 Questions

Question 1

Which of these is NOT a naming convention for discovery in pytest?

Accepted Answer

suite_*.py. Files starting with 'test_' or ending with '_test.py' are discovered. 'spec_test.py' would be discovered, but files like 'example.py' are ignored unless explicitly configured.

Answer

test_*.py

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*_test.py

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test_*.py

Question 2

In pytest, how can you skip a test based on the operating system platform?

Accepted Answer

@pytest.mark.skipif(sys.platform == 'win32'). The @pytest.mark.skipif decorator allows for conditional skipping based on expressions like sys.platform.

Answer

pytest.ignore_if(platform='win32')

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pytest.skip_on('win32')

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@pytest.skip(os='win32')

Question 3

Which 'unittest' assertion is best suited to verify that two floating-point numbers are equal within a certain tolerance?

Accepted Answer

assertAlmostEqual. assertAlmostEqual is specifically designed to handle floating-point precision issues by comparing values within a specified delta.

Answer

assertGreater

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assertEqual

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assertSequenceEqual

Question 4

You need to mock an object that is imported into a module. Which patch strategy correctly replaces the object where it is used?

Accepted Answer

Patch the object at the import location within the module being tested.. You must patch the object in the namespace where it is imported (the destination), not where it is defined, to ensure the replacement takes effect.

Answer

Use a global variable to override the module import.

Answer

Patch the object at its definition location.

Answer

Modify sys.modules directly.

Question 5

When using the 'unittest' framework, which method is executed exactly once before any test methods in a class are run?

Accepted Answer

setUpClass. The 'setUpClass' method is a class method that runs once before all tests in the class, whereas 'setUp' runs before each individual test.

Answer

setUp

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pre_test

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init

Question 6

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 7

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

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with pytest.assert_raises(CustomError):

Question 8

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 9

When using 'unittest.mock.MagicMock', what happens when you access an attribute that hasn't been defined?

Accepted Answer

It returns a new MagicMock instance.. MagicMock instances automatically create new MagicMock objects when you access previously undefined attributes.

Answer

It returns None.

Answer

It returns the string 'undefined'.

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It raises an AttributeError.

Question 10

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

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-f

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--halt

Question 11

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

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pytest.loop()

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@pytest.fixture(params=...)

Question 12

When using 'unittest', how do you ensure that a teardown method runs even if the test method raises an exception?

Accepted Answer

The framework automatically calls tearDown().. The 'tearDown' method is guaranteed to run by the unittest framework regardless of the test outcome, assuming setup succeeded.

Answer

You must check 'self.failureException'.

Answer

You must use the 'addCleanup' method.

Answer

Use a try-finally block inside the test method.

Question 13

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

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python -m unittest discover

Answer

pytest --execute-all

Question 14

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.

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Use the --shared-fixtures flag.

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Import it in every file.

Question 15

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

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pytest_init

Question 16

When asserting that a mock was called with specific arguments, which method should be used to verify the call history?

Accepted Answer

mock.assert_called_with(). assert_called_with is the standard method for verifying the most recent call or the specific instance of a call.

Answer

mock.verify_args()

Answer

mock.check_args()

Answer

mock.called_with()

Question 17

What is the purpose of the 'autospec' argument in 'patch'?

Accepted Answer

It creates a mock with the same API as the original object.. autospec ensures the mock has the same attributes and methods as the object it is replacing, preventing tests from passing when they call non-existent methods.

Answer

It speeds up test execution.

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It automatically generates a return value.

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It automatically documents the mock calls.

Question 18

How do you check how many times a mock object was called?

Accepted Answer

mock.call_count. The 'call_count' attribute on a MagicMock or Mock object keeps track of the number of times it has been called.

Answer

mock.called_times

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len(mock.calls)

Answer

mock.get_call_count()

Question 19

What is the purpose of 'pytest.mark.xfail'?

Accepted Answer

To allow a known failure to not break the build.. It marks a test as expected to fail, allowing the build to pass even if the test fails.

Answer

To debug a failing test.

Answer

To force a test to fail.

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To skip a test temporarily.

Question 20

Which TWO of the following are valid ways to pass data into a pytest test function?

Accepted Answer

Using function arguments that match fixture names. Fixtures and parametrization are the standard ways to inject data into pytest functions.

Answer

Defining global variables in the same file

Answer

Accessing the 'sys.argv' list

Answer

Using the 'unittest.TestCase' setup method