Fixture factories in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple fixture factory

What is the output of this pytest test when run?

Note: The fixture factory creates a user object with a given name.

PyTest

import pytest

@pytest.fixture
def user_factory():
    def create_user(name):
        return {"name": name, "active": True}
    return create_user

def test_user_active(user_factory):
    user = user_factory("Alice")
    assert user["active"]
    print(user["name"])

A KeyError

B True

C Alice

D AssertionError

💡 Hint

Focus on what the fixture factory returns and what the test prints.

The fixture factory returns a function that creates a user dict with the given name and active status True. The test asserts active is True (passes) and prints the name, which is 'Alice'.

❓ assertion

intermediate

Correct assertion for fixture factory output

Given this fixture factory, which assertion correctly verifies the created user's age is 30?

PyTest

import pytest

@pytest.fixture
def user_factory():
    def create_user(name, age):
        return {"name": name, "age": age}
    return create_user

def test_user_age(user_factory):
    user = user_factory("Bob", 30)
    # Which assertion is correct here?

A assert user["age"] == 30

B assert user.age == 30

C assert user.get("name") == 30

D assert user["age"] != 30

💡 Hint

Remember how dictionaries are accessed in Python.

The user is a dictionary, so to check age, use user["age"] == 30. Option A fails because dicts don't have attribute access. Option A checks name, not age. Option A asserts the opposite.

🔧 Debug

advanced

Identify the error in fixture factory usage

This test fails with a TypeError. What is the cause?

Code:
import pytest @pytest.fixture def user_factory(): def create_user(name, age=25): return {"name": name, "age": age} return create_user def test_user(user_factory): user = user_factory() assert user["age"] == 25

A user_factory() is called without required positional argument 'name'

B The fixture factory returns None instead of a function

C The assertion compares wrong key 'age' instead of 'name'

D The fixture is missing the @pytest.mark.usefixtures decorator

💡 Hint

Check the parameters of the inner function and how it is called.

The inner function create_user requires 'name' as a positional argument without default. Calling user_factory() without arguments causes TypeError.

❓ framework

advanced

Best practice for fixture factory scope

Which scope is most appropriate for a fixture factory that creates fresh test data for each test?

A "class" scope to share data across test methods in a class

B "module" scope to reuse data across tests in a module

C "session" scope to share data across all tests in session

D "function" scope to ensure fresh data per test

💡 Hint

Think about test isolation and data freshness.

Function scope runs the fixture for each test function, ensuring fresh data. Other scopes reuse data, risking shared state.

🧠 Conceptual

expert

Why use fixture factories instead of simple fixtures?

Which reason best explains why fixture factories are preferred over simple fixtures when creating test objects with varying attributes?

A Fixture factories reduce the number of test functions needed

B Fixture factories allow dynamic creation of objects with different parameters per test

C Simple fixtures run faster and are better for varying test data

D Simple fixtures automatically reset database state between tests

💡 Hint

Consider flexibility in test data creation.

Fixture factories return functions that accept parameters, enabling tests to create customized objects. Simple fixtures return fixed data.