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Testing & modern typing

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

4 matches

How to Compare Execution Speed Between Python Functions

Measure and compare the average execution time of multiple Python functions using a reusable benchmark helper with time.perf_counter.

performance benchmarking time

Python

import time
import random

def method_a(values):
    """Sort using built-in sorted."""
    return sorted(values)

def method_b(values):
    """Sort using list's sort method."""
    values_copy = values[:]
    values_copy.sort()
    return values_copy

def method_c(values):
    """Sort manually using bubble sort (slow,…

38 0 Open

Testing & modern typing easy

How to Compare Files and Show a Diff in Python

Compare two text files and print a unified diff using Python's difflib module to highlight differences.

diff files difflib

Python

import difflib
from pathlib import Path

def compare_files(expected_path: str, actual_path: str) -> str:
    """Compare two text files and return a unified diff."""
    expected = Path(expected_path).read_text()
    actual = Path(actual_path).read_text()

    diff = difflib.unified_diff(
        expected.splitlines(ke…

10 0 Open

Testing & modern typing easy

How to Test Environment Variables with pytest monkeypatch in Python

Shows how to use pytest's monkeypatch fixture to set and delete environment variables for isolated tests.

pytest monkeypatch environment variables

Python

import os
import pytest

def get_database_url():
    return os.getenv("DATABASE_URL", "postgres://default")

def test_database_url_with_env(monkeypatch):
    monkeypatch.setenv("DATABASE_URL", "postgres://test-db")
    assert get_database_url() == "postgres://test-db"

def test_database_url_default(monkeypatch):
    m…

12 0 Open

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.…

19 0 Open

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