Why mocking isolates code under test in PyTest - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the mocking tool.

PyTest

from unittest.mock import [1]

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Amock

BTestCase

CMagicMock

Dpatch

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'mock' instead of 'patch' which is the correct function to replace objects.

Importing 'TestCase' which is for test classes, not mocking.

The patch function is used to replace parts of your system under test with mock objects.

2fill in blank

medium

Complete the code to mock the requests.get method in the test.

PyTest

@patch('[1]')
def test_fetch_data(mock_get):
    mock_get.return_value.status_code = 200
    assert fetch_data() == 'Success'

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Arequests.get

Brequests.post

Cfetch_data

Dmock_get

Attempts:

3 left

💡 Hint

Common Mistakes

Mocking 'requests.post' which is not called in the function.

Mocking 'fetch_data' itself instead of its dependency.

We mock requests.get because fetch_data calls it to get data from the internet.

3fill in blank

hard

Fix the error in the test by completing the mock patch target correctly.

PyTest

@patch('[1]')
def test_process_data(mock_func):
    mock_func.return_value = 42
    result = process_data()
    assert result == 42

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Amodule_under_test.external_api_call

Bexternal_api_call

Cprocess_data.external_api_call

Dmodule_under_test.process_data

Attempts:

3 left

💡 Hint

Common Mistakes

Patching the global function name instead of the module's reference.

Patching the function under test itself.

The patch target must be the name used in the module under test, not the global function name.

4fill in blank

hard

Fill both blanks to mock a database call and check the return value.

PyTest

@patch('[1]')
def test_get_user(mock_db_call):
    mock_db_call.return_value = [2]
    user = get_user(1)
    assert user == {'id': 1, 'name': 'Alice'}

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Adatabase.fetch_user

B{'id': 1, 'name': 'Alice'}

C{'id': 2, 'name': 'Bob'}

Ddatabase.get_user

Attempts:

3 left

💡 Hint

Common Mistakes

Mocking the wrong database function.

Returning a user dictionary that does not match the test assertion.

We mock database.fetch_user to return the expected user dictionary for the test.

5fill in blank

hard

Fill all three blanks to mock a service call, set its return value, and assert the call count.

PyTest

@patch('[1]')
def test_service_call(mock_service):
    mock_service.return_value = [2]
    result = call_service()
    mock_service.[3]()
    assert result == 'OK'

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Aservices.api_call

B'OK'

Cassert_called_once

Dassert_called_once_with

Attempts:

3 left

💡 Hint

Common Mistakes

Using assert_called_once_with without arguments when the call has none.

Setting the wrong return value that does not match the assertion.

We patch services.api_call, set its return to 'OK', and check it was called once.