Grouping related tests in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of grouped pytest tests with fixtures

Consider the following pytest code with a fixture and two test functions grouped in a class. What will be the output when running pytest on this file?

PyTest

import pytest

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

class TestGroup:
    def test_sum(self, setup_data):
        assert sum(setup_data) == 6

    def test_len(self, setup_data):
        assert len(setup_data) == 3

A Both tests pass successfully.

B Both tests fail due to fixture error.

C test_sum passes, test_len fails.

D test_sum fails, test_len passes.

💡 Hint

Think about what the fixture returns and the assertions in each test.

The fixture 'setup_data' returns a list [1, 2, 3]. The sum is 6 and length is 3, so both assertions are true and tests pass.

❓ assertion

intermediate

Correct assertion to check all items in a grouped test

You have a grouped test that checks if all items in a list are positive. Which assertion correctly verifies this in pytest?

PyTest

def test_all_positive():
    data = [5, 10, 15]
    # Which assertion is correct here?

A assert data > 0

B assert any(x > 0 for x in data)

C assert sum(data) > 0

D assert all(x > 0 for x in data)

💡 Hint

Think about checking every item, not just some or the sum.

Using all() ensures every item is greater than zero, which matches the test goal.

🔧 Debug

advanced

Identify the cause of test skipping in grouped pytest tests

Given this pytest code, why is the test 'test_feature' skipped when running the group?

PyTest

import pytest

@pytest.mark.skipif(True, reason="Feature not ready")
class TestFeatures:
    def test_feature(self):
        assert True

A The test is skipped because the assertion is True.

B The skipif decorator on the class causes all tests inside to be skipped.

C The test is skipped due to a syntax error in the code.

D The test is skipped because pytest cannot find the test function.

💡 Hint

Look at the decorator and its condition.

The @pytest.mark.skipif(True) on the class causes pytest to skip all tests inside unconditionally.

❓ framework

advanced

Best practice for grouping tests in pytest

Which of the following is the best practice to group related tests in pytest for better organization and reuse?

A Group tests inside classes without __init__ and use fixtures for setup.

B Group tests inside classes with __init__ methods to initialize data.

C Write all tests as standalone functions without grouping.

D Use global variables to share data between tests.

💡 Hint

Think about pytest conventions and fixture usage.

Pytest recommends grouping tests in classes without __init__ and using fixtures for setup to keep tests isolated and organized.

🧠 Conceptual

expert

Effect of test grouping on test discovery and execution order in pytest

In pytest, how does grouping tests inside classes affect test discovery and execution order compared to standalone test functions?

A Grouping tests inside classes disables test discovery for those tests.

B Tests inside classes are discovered but run in random order; standalone functions run alphabetically.

C Tests inside classes are discovered and run in the order they appear; standalone functions run in file order.

D Grouping tests inside classes causes tests to run before standalone functions always.

💡 Hint

Consider how pytest collects and orders tests.

Pytest discovers tests in file order. Tests inside classes run in the order they appear in the class, preserving grouping order.