Fixture finalization (request.addfinalizer) in PyTest - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of request.addfinalizer in pytest fixtures?

request.addfinalizer is used to register a cleanup function that runs after the test using the fixture finishes. It helps to release resources or reset states.

intermediate

How does request.addfinalizer differ from using yield in pytest fixtures?

request.addfinalizer registers a cleanup callback explicitly, while yield splits the fixture into setup and teardown parts. Both achieve cleanup but with different syntax.

beginner

Write a simple pytest fixture that opens a file and uses request.addfinalizer to close it.

<pre>import pytest

@pytest.fixture
def open_file(request):
    f = open('test.txt', 'w')
    def close_file():
        f.close()
    request.addfinalizer(close_file)
    return f</pre>

beginner

When is the finalizer function registered by request.addfinalizer executed?

The finalizer function runs after the test function finishes, regardless of whether the test passed or failed. It ensures cleanup always happens.

intermediate

Can multiple finalizers be added with request.addfinalizer in one fixture? What happens?

Yes, you can add multiple finalizers. They run in the reverse order of registration after the test completes.

What does request.addfinalizer do in a pytest fixture?

A Registers a function to run after the test for cleanup

B Starts the test execution

C Skips the test

D Marks the test as failed

request.addfinalizer registers a cleanup function to run after the test finishes.

When is the finalizer function executed in pytest fixtures using request.addfinalizer?

A After the test finishes

B Before the test starts

C Only if the test passes

D Only if the test fails

The finalizer runs after the test finishes, regardless of the test result.

Which of the following is a correct way to add a finalizer in a pytest fixture?

A request.addfinalize(cleanup_function)

B request.finalize(cleanup_function)

C request.addfinalizer(cleanup_function)

D request.cleanup(cleanup_function)

The correct method is request.addfinalizer.

If you add multiple finalizers with request.addfinalizer, in what order do they run?

A In the order they were added

B In reverse order of addition

C Random order

D They run simultaneously

Finalizers run in reverse order of registration.

Which is a benefit of using request.addfinalizer over yield in fixtures?

A Runs cleanup only on test failure

B Runs cleanup before setup

C Skips the test automatically

D Allows multiple cleanup functions

request.addfinalizer can register multiple cleanup functions easily.

Explain how request.addfinalizer works in pytest fixtures and why it is useful.

Think about cleaning up after using something in a test.

Describe the difference between using request.addfinalizer and yield in pytest fixtures for cleanup.

One uses a function call, the other uses Python's yield keyword.