Mock and MagicMock in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a mock object using unittest.mock.

PyTest

from unittest.mock import [1]

mock_obj = [1]()

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AMock

BMagicMock

Cpatch

Dcall

Attempts:

3 left

💡 Hint

Common Mistakes

Using MagicMock when only a basic mock is needed.

Using patch instead of Mock to create a mock object.

The Mock class is used to create a basic mock object in unittest.mock.

2fill in blank

medium

Complete the code to assert that a mock method was called exactly once.

PyTest

mock_obj.method()

mock_obj.method.[1]()

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Aassert_called

Bassert_called_once_with

Cassert_called_once

Dassert_not_called

Attempts:

3 left

💡 Hint

Common Mistakes

Using assert_called which only checks if called at least once.

Using assert_called_once_with which also checks call arguments.

assert_called_once() checks that the mock method was called exactly one time.

3fill in blank

hard

Fix the error in the code to set a return value for a mock method.

PyTest

mock_obj = MagicMock()
mock_obj.get_data.[1] = 42

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Aside_effect

Bvalue

Creturn

Dreturn_value

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'return' which is a keyword, not an attribute.

Using 'side_effect' when only a fixed return value is needed.

The return_value attribute sets what the mock method returns when called.

4fill in blank

hard

Fill both blanks to patch a function and check it was called with specific arguments.

PyTest

from unittest.mock import patch

with patch('module.func') as mock_func:
    mock_func([1])
    mock_func.[2]('hello', 5)

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A'hello', 5

Bassert_called_with

Cassert_called_once

D'test', 10

Attempts:

3 left

💡 Hint

Common Mistakes

Using assert_called_once which checks call count but not arguments.

Passing wrong arguments to the mock function call.

The patched function is called with arguments 'hello' and 5, then assert_called_with checks those exact arguments.

5fill in blank

hard

Fill all three blanks to create a MagicMock, set a side effect, and verify the exception is raised.

PyTest

from unittest.mock import MagicMock
import pytest

mock_func = MagicMock()
mock_func.side_effect = [1]

with pytest.raises([2]):
    mock_func([3])

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AValueError

BException

Clambda x: (_ for _ in ()).throw(ValueError('error'))

D42

Attempts:

3 left

💡 Hint

Common Mistakes

Setting side_effect to an exception instance instead of a callable.

Using wrong exception type in pytest.raises.

Calling mock_func without arguments when side_effect expects one.

The side_effect is set to a lambda that raises ValueError. The test checks that calling mock_func(42) raises ValueError.