Basic assert statement in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this pytest assertion?

Consider the following pytest test function. What will be the test result when running it?

PyTest

def test_sum():
    result = sum([1, 2, 3])
    assert result == 6

A Test passes successfully

B Test fails with AssertionError

C SyntaxError during test execution

D TypeError during test execution

💡 Hint

Check if the sum of the list matches the asserted value.

The sum of [1, 2, 3] is 6, which matches the assertion, so the test passes.

❓ assertion

intermediate

Which assertion correctly checks if a string contains a substring?

You want to assert that the string 'hello world' contains 'world'. Which assertion is correct?

A assert 'world' not in 'hello world'

B assert 'hello world'.contains('world')

C assert 'world' == 'hello world'

D assert 'world' in 'hello world'

💡 Hint

Use Python's membership operator for substring checks.

Option D uses the correct syntax to check substring presence with 'in'. Option D is invalid syntax, C checks equality incorrectly, and D asserts the opposite.

🔧 Debug

advanced

Why does this pytest assertion fail?

Given the test below, why does it fail?

PyTest

def test_list_length():
    items = [1, 2, 3]
    assert len(items) == 3

A SyntaxError due to wrong assignment operator in assertion

B AssertionError because length is not 3

C TypeError because len() returns a string

D Test passes successfully

💡 Hint

Check the operator used in the assert statement.

The assertion uses '=' which is assignment, not comparison. This causes a SyntaxError.

🧠 Conceptual

advanced

What happens if an assertion fails in pytest?

In pytest, when an assert statement fails inside a test function, what is the outcome?

A The test is skipped without any error

B The test is marked as failed and pytest reports AssertionError

C The test passes but with a warning

D The test runner crashes and stops all tests

💡 Hint

Think about how pytest handles failed assertions.

Pytest marks the test as failed and shows the AssertionError details when an assert fails.

❓ framework

expert

Which pytest feature helps to show detailed info on assert failures automatically?

You want pytest to show detailed values in assert failure messages without writing custom messages. Which feature enables this?

A pytest.mark.parametrize decorator

B Using assert with custom message parameter

C pytest's assert rewriting feature

D pytest.skip marker

💡 Hint

This feature modifies assert statements to provide better failure details.

Pytest rewrites assert statements to show detailed info on failure automatically, called assert rewriting.