[Solved] Consider this fixture in conftest.py:@pytest.fixture def items(): return [1, 2, 3]and the test:def test_append(items): items.... | PyTest

PyTest - Fixtures

Consider this fixture in conftest.py:

@pytest.fixture
def items():
    return [1, 2, 3]

and the test:

def test_append(items):
    items.append(4)
    assert items == [1, 2, 3, 4]

What issue might arise when running multiple tests using this fixture?

APytest will raise an error about modifying fixtures.

BThe list is shared and mutated across tests, causing side effects.

CThe fixture returns a new list each time, so no issues occur.

DThe test will always fail because append is not allowed.

Step-by-Step Solution

Solution:

Step 1: Understand fixture behavior
By default, fixtures have function scope and return a new list each time.
Step 2: Mutation in test
The test mutates the list by appending an element.
Step 3: Potential problem
If the fixture is changed to a broader scope (e.g., module or session), the list would be shared and mutations persist across tests, causing side effects.
Step 4: Conclusion
Mutating shared fixtures can lead to flaky tests.
Final Answer:
The fixture returns a new list each time, so no issues occur. -> Option C
Quick Check:
Function-scoped fixture returns fresh data each test [OK]

Quick Trick: Avoid mutating fixtures with broader scopes [OK]

Common Mistakes:

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