Code Quiz

Patching the Wrong Target in pytest

Spot the classic mock.patch mistake that leaves the real function running during a pytest unit test.

Codepython

# app/service.py
from app.clients import fetch_user

def greet_user(user_id):
    user = fetch_user(user_id)
    return f"Hello, {user['name']}!"

# tests/test_service.py
from unittest.mock import patch
from app.service import greet_user

@patch("app.clients.fetch_user")
def test_greet_user(mock_fetch):
    mock_fetch.return_value = {"name": "Ada"}
    result = greet_user(42)
    assert result == "Hello, Ada!"

The test still calls the real network client instead of the mock. What is the bug?

Next →Patching the Right Namespace in pytest