Asserting exceptions (pytest.raises) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assert that a ValueError is raised.

PyTest

import pytest

def test_value_error():
    with pytest.[1](ValueError):
        int('abc')

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

Araises

Braises_error

Cassert

Dexpect

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'assert' instead of 'raises' causes syntax errors.

Using a wrong function name like 'raises_error' will fail.

The pytest.raises context manager is used to check if the specified exception is raised.

2fill in blank

medium

Complete the code to check the exception message contains 'invalid literal'.

PyTest

import pytest

def test_error_message():
    with pytest.raises(ValueError) as [1]:
        int('abc')
    assert 'invalid literal' in [1].value.args[0]

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

Aexception

Berror

Cexcinfo

Derr

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name not matching the assertion line causes NameError.

Forgetting to use 'as' to capture exception info.

The variable after as captures the exception info object, commonly named excinfo.

3fill in blank

hard

Fix the error in the code to properly assert a ZeroDivisionError is raised.

PyTest

import pytest

def test_division():
    with pytest.raises([1]):
        result = 1 / 0

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

AValueError

BZeroDivisionError

CTypeError

DIndexError

Attempts:

3 left

💡 Hint

Common Mistakes

Using ValueError or other exceptions causes the test to fail.

Misspelling the exception name.

The exception raised by dividing by zero is ZeroDivisionError.

4fill in blank

hard

Fill both blanks to assert a KeyError is raised and check its message.

PyTest

import pytest

def test_key_error():
    with pytest.[1](KeyError) as [2]:
        d = {}
        d['missing']

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

Araises

Berror

Cexcinfo

Dexpect

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong context manager name causes syntax errors.

Using a variable name not matching the assertion line.

Use raises as the context manager and excinfo to capture the exception info.

5fill in blank

hard

Fill all three blanks to assert a TypeError is raised and check the exception message contains 'unsupported operand'.

PyTest

import pytest

def test_type_error():
    with pytest.[1](TypeError) as [2]:
        result = 'a' + 1
    assert '[3]' in [2].value.args[0]

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

Araises

Bexcinfo

Cunsupported operand

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong exception type or variable name.

Checking for wrong message text.

Use raises to catch the exception, excinfo to capture it, and check the message contains unsupported operand.