Test naming conventions in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest test discovery with naming

Given the following test functions in a file named test_math.py, which tests will pytest discover and run?

PyTest

def test_addition():
    assert 1 + 1 == 2

def check_subtraction():
    assert 2 - 1 == 1

def testMultiply():
    assert 2 * 3 == 6

class TestOperations:
    def test_divide(self):
        assert 6 / 2 == 3
    def divide_test(self):
        assert 6 / 3 == 2

A test_addition, testMultiply, test_divide

B test_addition, test_divide

C test_addition, check_subtraction, testMultiply, test_divide, divide_test

D test_addition, testMultiply, test_divide, divide_test

💡 Hint

pytest discovers test functions and methods that start with test_ or are in classes named Test* with methods starting with test_.

pytest discovers functions starting with test_ and methods in classes named Test* starting with test_. So test_addition, testMultiply (not starting with test_), and test_divide are considered. However, testMultiply does not start with test_ so it is not discovered. The correct discovered tests are test_addition and test_divide. But testMultiply is not discovered. So only test_addition and test_divide run. Option B incorrectly includes testMultiply. Reconsider options carefully.

❓ assertion

intermediate

Correct assertion for test function name check

Which assertion correctly verifies that a test function name func_name follows pytest naming conventions?

PyTest

func_name = "test_example"

A assert func_name.startswith("test_")

B assert func_name.endswith("_test")

C assert "test" in func_name

D assert func_name == "testExample"

💡 Hint

pytest requires test function names to start with test_.

The correct assertion checks if the function name starts with test_. Option A does this correctly. Option A checks the wrong end of the string. Option A is too broad and allows names like mytestfunc. Option A checks for an exact name which is not general.

🔧 Debug

advanced

Identify why pytest skips a test function

Why does pytest skip the following test function during discovery?

PyTest

def Test_login():
    assert True

A Function is missing a decorator to mark it as a test

B Function is inside a class without 'Test' prefix

C Function name is too short

D Function name does not start with lowercase 'test_'

💡 Hint

pytest requires test functions to start with test_ in lowercase.

pytest discovers test functions only if their names start with lowercase test_. Here, the function name starts with uppercase T, so pytest skips it.

🧠 Conceptual

advanced

Best practice for test class naming in pytest

Which is the best practice for naming test classes in pytest to ensure test discovery?

A Class names should start with 'Test' and include an __init__ method

B Class names should start with 'test' in lowercase and have an __init__ method

C Class names should start with 'Test' and not have an __init__ method

D Class names can be any name as long as methods start with 'test_'

💡 Hint

pytest discovers test classes starting with 'Test' and ignores classes with __init__ methods.

pytest discovers test classes whose names start with 'Test' (uppercase T) and which do not define an __init__ method. Having an __init__ method prevents pytest from collecting tests in that class.

❓ framework

expert

Effect of pytest.ini on test naming conventions

Given the following pytest.ini configuration, which test function name will pytest discover?

[pytest]
testpaths = tests
python_files = check_*.py
python_functions = check_*

A def check_addition(): pass

B def test_addition(): pass

C def addition_check(): pass

D def add_check(): pass

💡 Hint

pytest.ini overrides default test discovery patterns.

The configuration changes pytest to look for files starting with 'check_' and functions starting with 'check_'. So only functions named like 'check_addition' are discovered. 'test_addition' is ignored because 'python_functions' is set to 'check_*'.