Checking exception attributes in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check that the exception message contains the word 'error'.

PyTest

import pytest

def test_error_message():
    with pytest.raises(ValueError) as exc_info:
        raise ValueError('This is an error message')
    assert 'error' in exc_info.value.[1][0]

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

Aargs

Btext

Cmessage

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'message' attribute which does not exist on the exception object.

Trying to access exc_info.message directly.

The args attribute of an exception contains the message as a tuple. Checking if 'error' is in exc_info.value.args verifies the message.

2fill in blank

medium

Complete the code to assert that the exception's first argument equals 'Invalid input'.

PyTest

import pytest

def test_invalid_input():
    with pytest.raises(ValueError) as exc_info:
        raise ValueError('Invalid input')
    assert exc_info.value.args[[1]] == 'Invalid input'

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

A-1

B1

C0

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 1 which is out of range for a single-argument exception.

Using negative index incorrectly.

The first argument of the exception message is at index 0 in the args tuple.

3fill in blank

hard

Fix the error in the code to correctly check the exception message contains 'timeout'.

PyTest

import pytest

def test_timeout_error():
    with pytest.raises(TimeoutError) as exc_info:
        raise TimeoutError('Connection timeout')
    assert 'timeout' in exc_info.value.[1][0]

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

Aargs

Btext

Cmsg

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent attributes like 'message' or 'msg'.

Trying to access exc_info.message directly.

The exception message is stored in args, not in message or other attributes.

4fill in blank

hard

Fill both blanks to check the exception type and that its message equals 'File not found'.

PyTest

import pytest

def test_file_error():
    with pytest.raises([1]) as exc_info:
        raise FileNotFoundError('File not found')
    assert exc_info.value.args[[2]] == 'File not found'

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

AFileNotFoundError

BValueError

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong exception type in pytest.raises.

Using index 1 instead of 0 for the message.

The exception type to catch is FileNotFoundError. The message is the first argument at index 0.

5fill in blank

hard

Fill all three blanks to assert the exception type, check the message contains 'denied', and verify the error code attribute equals 403.

PyTest

import pytest

class PermissionErrorWithCode(PermissionError):
    def __init__(self, message, code):
        super().__init__(message)
        self.code = code

def test_permission_error():
    with pytest.raises([1]) as exc_info:
        raise PermissionErrorWithCode('Access denied', 403)
    assert 'denied' in exc_info.value.args[[2]]
    assert exc_info.value.[3] == 403

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

APermissionErrorWithCode

B0

Ccode

DPermissionError

Attempts:

3 left

💡 Hint

Common Mistakes

Using the base PermissionError instead of the custom subclass.

Checking the message at wrong index.

Trying to access a non-existent attribute instead of 'code'.

The test catches the custom exception PermissionErrorWithCode. The message is the first argument at index 0. The custom attribute code is checked for the error code.