Asserting warnings (pytest.warns) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assert that a warning is raised.

PyTest

import warnings
import pytest

def test_warning():
    with pytest.warns([1]):
        warnings.warn("This is a warning", UserWarning)

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

AUserWarning

BRuntimeWarning

CDeprecationWarning

DWarning

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different warning type than the one raised causes the test to fail.

Not using pytest.warns() context manager.

The pytest.warns() context manager expects the warning class to check. Here, UserWarning matches the warning raised.

2fill in blank

medium

Complete the code to capture the warning message text.

PyTest

import warnings
import pytest

def test_warning_message():
    with pytest.warns(UserWarning) as record:
        warnings.warn("Check this warning", UserWarning)
    assert record[0].message.args[[1]] == "Check this warning"

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A2

B0

C1

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 1 or 2 which are out of range and cause errors.

Trying to access message attribute directly instead of args.

The warning message is stored as the first argument in args, so index 0 is correct.

3fill in blank

hard

Fix the error in the code to correctly assert a warning is raised.

PyTest

import warnings
import pytest

def test_warn():
    with pytest.warns([1]):
        warnings.warn("Deprecated", DeprecationWarning)

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

ADeprecationWarning

BUserWarning

CRuntimeWarning

DWarning

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different warning type causes the test to fail.

Not using a warning class but a string or variable.

The warning raised is DeprecationWarning, so pytest.warns() must check for the same type.

4fill in blank

hard

Fill both blanks to assert a warning and check its message.

PyTest

import warnings
import pytest

def test_warn_message():
    with pytest.warns([1]) as record:
        warnings.warn("Be careful", UserWarning)
    assert str(record[0].message) [2] "Be careful"

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AUserWarning

BDeprecationWarning

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong warning type in pytest.warns().

Using != instead of == in the assertion.

The warning type is UserWarning. The assertion checks if the message string equals "Be careful" using ==.

5fill in blank

hard

Fill all three blanks to assert a warning, capture it, and check the message content.

PyTest

import warnings
import pytest

def test_warning_content():
    with pytest.warns([1]) as record:
        warnings.warn("Use new API", [2])
    assert record[0].message.args[0] [3] "Use new API"

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

AUserWarning

BDeprecationWarning

C==

DRuntimeWarning

Attempts:

3 left

💡 Hint

Common Mistakes

Using different warning types in pytest.warns() and warnings.warn().

Using wrong comparison operators in the assertion.

The warning raised is DeprecationWarning, so both pytest.warns() and warnings.warn() use it. The assertion checks equality with ==.