Fixture scope (function, class, module, session) in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a fixture with function scope.

PyTest

import pytest

@pytest.fixture(scope=[1])
def sample_fixture():
    return 42

Drag options to blanks, or click blank then click option'

Afunction

Bclass

Cmodule

Dsession

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'class' or 'module' which run less frequently than function scope.

Using 'session' which runs once per test session.

The default fixture scope is function, which means the fixture is called once per test function.

2fill in blank

medium

Complete the code to set a fixture with class scope.

PyTest

import pytest

@pytest.fixture(scope=[1])
def class_fixture():
    return 'class level resource'

Drag options to blanks, or click blank then click option'

Amodule

Bsession

Cclass

Dfunction

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing class scope with function or module scope.

Using 'session' which is broader than class scope.

Class scope means the fixture is created once per test class and shared among all test methods in that class.

3fill in blank

hard

Fix the error in the fixture scope to make it run once per module.

PyTest

import pytest

@pytest.fixture(scope=[1])
def module_fixture():
    return 'module resource'

Drag options to blanks, or click blank then click option'

Afunction

Bclass

Csession

Dmodule

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' scope which runs once per class, not per module.

Using 'session' which runs once per entire test session.

Module scope means the fixture is created once per Python module and shared among all tests in that module.

4fill in blank

hard

Fill both blanks to create a session-scoped fixture and use it in a test.

PyTest

import pytest

@pytest.fixture(scope=[1])
def session_fixture():
    return 'session resource'

def test_example([2]):
    assert session_fixture == 'session resource'

Drag options to blanks, or click blank then click option'

Asession

Bfunction

Csession_fixture

Dmodule_fixture

Attempts:

3 left

💡 Hint

Common Mistakes

Not matching the fixture name in the test function parameter.

Using wrong scope like 'function' for session-wide resource.

The fixture is declared with session scope to run once per test session. The test function must accept the fixture name session_fixture as a parameter to use it.

5fill in blank

hard

Fill all three blanks to create a module-scoped fixture, use it in a test, and assert its value.

PyTest

import pytest

@pytest.fixture(scope=[1])
def mod_fixture():
    return 100

def test_mod([2]):
    assert [3] == 100

Drag options to blanks, or click blank then click option'

Amodule

Bmod_fixture

Dfunction

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong scope like 'function' instead of 'module'.

Mismatching fixture name in test function parameter or assertion.

The fixture has module scope, so it runs once per module. The test function uses the fixture by naming it mod_fixture as a parameter, and asserts that the fixture value equals 100.

Practice

1. What does the function scope mean for a pytest fixture?

easy

A. The fixture runs once per entire test session.

B. The fixture runs once per test class.

C. The fixture runs once per test module.

D. The fixture runs once per test function.

Solution

1. Step 1: Understand fixture scopes

   Pytest fixtures can have different scopes controlling how often they run.

2. Step 2: Define function scope meaning

   Function scope means the fixture runs before each test function and tears down after it.

3. Final Answer:

   The fixture runs once per test function. -> Option D

4. Quick Check:

   function scope = runs per test function [OK]

Hint: Function scope means run before every test function [OK]

Common Mistakes:

• Confusing function scope with class or module scope
• Thinking function scope runs once per class
• Assuming function scope runs once per session

2. Which of the following is the correct way to set a pytest fixture with module scope?

easy

A. @pytest.fixture(scope='module')

B. @pytest.fixture(scope='function')

C. @pytest.fixture(scope='class')

D. @pytest.fixture(scope='session')

Solution

1. Step 1: Recall fixture scope syntax

   To set a fixture scope, use @pytest.fixture(scope='scope_name').

2. Step 2: Match scope name for module

   The correct scope name for module is 'module'.

3. Final Answer:

   @pytest.fixture(scope='module') -> Option A

4. Quick Check:

   module scope syntax = scope='module' [OK]

Hint: Use scope='module' to run fixture once per file [OK]

Common Mistakes:

• Using 'session' instead of 'module' for module scope
• Forgetting to add scope parameter
• Using incorrect quotes or misspelling scope

3. Given this pytest code snippet, how many times will setup_db run?

import pytest

@pytest.fixture(scope='class')
def setup_db():
    print('Setup DB')

class TestA:
    def test_1(self, setup_db):
        pass
    def test_2(self, setup_db):
        pass

class TestB:
    def test_3(self, setup_db):
        pass

medium

A. 1 time

B. 3 times

C. 2 times

D. 4 times

Solution

1. Step 1: Understand class scope behavior

   Fixture with class scope runs once per test class, before any tests in that class.

2. Step 2: Count test classes using the fixture

   There are two test classes: TestA and TestB, each uses setup_db fixture.

3. Step 3: Calculate total runs

   setup_db runs once for TestA and once for TestB, total 2 times.

4. Final Answer:

   2 times -> Option C

5. Quick Check:

   class scope = once per class, 2 classes = 2 runs [OK]

Hint: Class scope runs once per test class [OK]

Common Mistakes:

• Counting runs per test method instead of per class
• Confusing class scope with function scope
• Ignoring multiple test classes

4. Identify the error in this pytest fixture usage:

import pytest

@pytest.fixture(scope='modul')
def setup_env():
    pass

def test_example(setup_env):
    assert True

medium

A. Missing @pytest.mark.usefixtures decorator.

B. Typo in scope value causes fixture not to run.

C. Fixture function must return a value.

D. Test function missing parentheses.

Solution

1. Step 1: Check fixture scope spelling

   The scope value 'modul' is misspelled; correct is 'module'.

2. Step 2: Understand effect of typo

   Pytest will not recognize the scope and may default or error, causing fixture not to run properly.

3. Final Answer:

   Typo in scope value causes fixture not to run. -> Option B

4. Quick Check:

   Scope must be spelled correctly [OK]

Hint: Check scope spelling carefully to avoid errors [OK]

Common Mistakes:

• Assuming fixture must return a value
• Confusing fixture decorator with marker
• Ignoring spelling errors in parameters

5. You want a pytest fixture to initialize a database connection once before all tests in multiple modules run, and close it after all tests finish. Which scope should you use and why?

hard

A. Use session scope to share across all tests in the run.

B. Use function scope to isolate each test.

C. Use module scope to share per file.

D. Use class scope to share per test class.

Solution

1. Step 1: Understand the requirement

   The database connection should be initialized once before all tests in multiple modules and closed after all tests.

2. Step 2: Match scope to requirement

   Session scope runs once per entire test session, perfect for setup/teardown across all modules.

3. Final Answer:

   Use session scope to share across all tests in the run. -> Option A

4. Quick Check:

   Session scope = once per test run [OK]

Hint: Session scope runs once for all tests in the run [OK]

Common Mistakes:

• Choosing function or class scope which run too often
• Using module scope which limits to one file
• Not matching scope to resource lifetime