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Testing & modern typing

pytest basics, mocks, type hints, TypedDict, Protocol, and static-checking patterns.

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Testing & modern typing medium

Use pytest fixture to mock a database connection in Python

This code shows how to use a pytest fixture and unittest.mock to replace a database connection with a Mock, enabling isolated tests without a real database.

pytest fixtures unittest.mock
Python 
import pytest
import sqlite3
from unittest.mock import Mock

class Database:
    def __init__(self, connection):
        self.connection = connection

    def get_user(self, user_id):
        cursor = self.connection.cursor()
        cursor.execute("SELECT * FROM users WHERE id = ?", (user_id,))
        return cursor.…
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