Testing & modern typing

def legacy_behavior(value):
    """Legacy function that returns a tuple with unconventional types."""
    if value == "special":
        return None, "legacy-special"
    elif value > 100:
        return value, "large"
    elif value > 0:
        return value * 2, "positive-doubled"
    elif value == 0:
     …

import time
from unittest.mock import Mock, patch

import pytest
from pytest_benchmark.fixture import BenchmarkFixture


def heavy_operation(data: list[int]) -> int:
    """Simulates a CPU-bound operation."""
    return sum(x * x for x in data)


def test_heavy_operation_benchmark(benchmark: BenchmarkFixture) -> None:…

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,…

import difflib

def snapshot_diff(before, after, intentional_changes=None):
    """Compare snapshots and flag only unexpected differences."""
    intentional_changes = intentional_changes or set()
    diff = list(difflib.unified_diff(before, after, lineterm=""))
    has_unexpected = False

    for line in diff:
      …

from locust import HttpUser, task, between


class WebsiteUser(HttpUser):
    wait_time = between(1, 3)

    @task
    def home_page(self):
        self.client.get("/")

    @task(3)
    def about_page(self):
        self.client.get("/about")


if __name__ == "__main__":
    print("Run with: locust -f this_file.py --h…

import factory
from dataclasses import dataclass
from unittest.mock import Mock, patch
import builtins


@dataclass
class User:
    name: str
    age: int


class UserFactory(factory.Factory):
    class Meta:
        model = User

    name = "Alice"
    age = 30


def get_user_name(user):
    return user.name


def ma…

import unittest
from unittest.mock import patch

class Calculator:
    def add(self, a, b):
        return a + b
    
    def multiply(self, a, b):
        return a * b

class TestCalculator(unittest.TestCase):
    def test_add_normal(self):
        calc = Calculator()
        result = calc.add(2, 3)
        self.asse…

import re
from unittest.mock import patch
from playwright.sync_api import sync_playwright

def verify_api_mock(page, mock_url, mock_response):
    with patch("playwright.sync_api.APIRequestContext.get") as mock_get:
        mock_get.return_value.json.return_value = mock_response
        mock_get.return_value.status_co…

import os
import subprocess
import tempfile
from pathlib import Path


def sample_function(x: int) -> int:
    """A simple function to demonstrate coverage."""
    if x > 0:
        return x * 2
    else:
        return -x


def run_pytest_with_coverage() -> str:
    """Run pytest with coverage on a temp project and r…

import subprocess
import json
from typing import Dict

def run_integration_test() -> Dict[str, str]:
    """
    Simulates an integration test against a docker-compose environment
    using a mock service that returns canned responses.
    """
    # Mock docker-compose environment check
    env_ready = subprocess.run(…

import json
from unittest.mock import Mock, patch
import pytest


def load_config(data):
    config = json.loads(data)
    return {"host": config["host"], "port": config["port"]}


def test_load_config_snapshot(snapshot):
    mock_data = json.dumps({"host": "localhost", "port": 8080, "extra": "ignored"})
    result = …

import random
import string


def generate_random_string(length: int) -> str:
    """Generate a random alphanumeric string of given length."""
    chars = string.ascii_letters + string.digits
    return "".join(random.choice(chars) for _ in range(length))


def reverse_twice_is_identity(s: str) -> bool:
    """Propert…

from hypothesis import given, strategies as st
from hypothesis import example


@given(st.lists(st.text(min_size=1, max_size=10), min_size=1, max_size=5))
def test_joined_string_length(items):
    """Each text is non-empty; a joined string should be at least as long
    as the number of items (separator adds character…

import random

# In mutation testing, a "mock flip" intentionally changes a Boolean
# constant to False (or True) to see if the test suite catches it.
# This is a common "constant mutation" applied to a source file's literals.

def is_even(n: int) -> bool:
    """Return True if n is even. Contains a Boolean literal us…

class PaymentGateway:
    def charge(self, amount):
        raise NotImplementedError


class StubPaymentGateway(PaymentGateway):
    """Returns a fixed response without any logic."""
    def charge(self, amount):
        return {"success": True, "transaction_id": "stub-12345"}


class FakePaymentGateway(PaymentGatewa…

from typing import Any, Dict, List, Optional, Union, TypedDict, Literal

class Product(TypedDict):
    product_id: int
    name: str
    price: Union[int, float]
    in_stock: bool
    tags: Optional[List[str]]

def validate_product(data: Dict[str, Any]) -> Product:
    product_id: int = int(data["product_id"])
    na…

from typing import Any, Optional, Union, TypeVar, get_origin, get_args

T = TypeVar("T")

def validate(value: Any, expected_type: type) -> Optional[str]:
    """Returns an error message if value doesn't match expected_type, else None."""
    # Handle Optional[...] types
    origin = get_origin(expected_type)
    if or…

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.…