Tip for clean tests in Python:

Structure your tests with the Arrange-Act-Assert pattern to improve readability and maintainability.

• Arrange: Set up the test. Initialize objects, prepare data, and configure any mocks or stubs.
• Act: Execute the code being tested. Call the specific function or method.
• Assert: Check the outcome. Verify that the result of the action is what you expected.

import pytest
from dataclasses import dataclass, field


# Code to be tested
@dataclass
class Product:
    name: str
    price: float


@dataclass
class ShoppingCart:
    items: list[Product] = field(default_factory=list)

    def add_item(self, product: Product):
        if product.price < 0:
            raise ValueError("Product price cannot be negative.")
        self.items.append(product)

    def get_total_price(self) -> float:
        return sum(item.price for item in self.items)


# Tests using the Arrange-Act-Assert pattern
def test_get_total_price_for_multiple_items():
    # Arrange
    product1 = Product(name="Mouse", price=25.50)
    product2 = Product(name="Keyboard", price=75.50)
    cart = ShoppingCart()
    cart.add_item(product1)
    cart.add_item(product2)

    # Act
    total_price = cart.get_total_price()

    # Assert
    assert total_price == 101.00


def test_get_total_price_for_empty_cart():
    # Arrange
    cart = ShoppingCart()

    # Act
    total_price = cart.get_total_price()

    # Assert
    assert total_price == 0.0


def test_add_item_with_negative_price_raises_value_error():
    # Arrange
    cart = ShoppingCart()
    product_with_negative_price = Product(name="Invalid Item", price=-50.0)

    # Act & Assert
    with pytest.raises(ValueError, match="Product price cannot be negative."):
        cart.add_item(product_with_negative_price)

#Python #Testing #CleanCode #SoftwareEngineering #Pytest #DeveloperTips #AAA

━━━━━━━━━━━━━━━
By: @DataScienceQ ✨

Hello! How can I assist you today?

By: @DataScienceQ 🚀

300 Real Time SQL Interview practical Questions Asked at multiple companies
••••••••••••••••••••••••••••••••••••••••••••••••••••••

Anyone who's preparing for an interview just reading theoretical concept will not help definitely you need to have practical hands on in #sql so create table with some data and try this queries running by your self so can help you to understand the logic of similar kind of queries

If you're preparing for an interview this doc will help a lot in the perpetration If you're experienced also freshers can also get hands on by practicing these queries and get confidence.

https://news.1rj.ru/str/DataScienceQ

🚀 THE 7-DAY PROFIT CHALLENGE! 🚀

Can you turn $100 into $5,000 in just 7 days?
Lisa can. And she’s challenging YOU to do the same. 👇

https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi
https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi
https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi

🚀 THE 7-DAY PROFIT CHALLENGE! 🚀

Can you turn $100 into $5,000 in just 7 days?
Lisa can. And she’s challenging YOU to do the same. 👇

https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi
https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi
https://news.1rj.ru/str/+AOPQVJRWlJc5ZGRi

💸 PacketSDK--A New Way To Make Revenue From Your Apps

Regardless of whether your app is on desktop, mobile, TV, or Unity platforms, no matter which app monetization tools you’re using, PacketSDK can bring you additional revenue!

● Working Principle: Convert your app's active users into profits 👥→💵

● Product Features: Ad-free monetization 🚫, no user interference

● Additional Revenue: Fully compatible with your existing ad SDKs

● CCPA & GDPR: Based on user consent, no collection of any personal data 🔒

● Easy Integration: Only a few simple steps, taking approximately 30 minutes

Join us：https://www.packetsdk.com/?utm-source=SyWayQNK

Contact us & Estimated income:
Telegram:@Packet_SDK
Whatsapp:https://wa.me/85256440384
Teams:https://teams.live.com/l/invite/FBA_1zP2ehmA6Jn4AI

⏰ Join early ,earn early!

⛓️ Tricky Python Interview Question

> What will this code output and why?

funcs = []
for i in range(3):
    funcs.append(lambda: print(i))

for f in funcs:
    f()

❓ Question: Why does this code print 2, 2, 2 instead of 0, 1, 2?

🔍 Explanation:

This is a classic example of late binding in Python closures. The lambda functions don't capture the value of i at each step of the loop. Instead, they all hold a reference to the same variable i.

🧠 What happens:

• The for loop completes. By the end of the loop, the variable i holds the value 2.
• The funcs list contains three functions, but each one is defined to print the value of whatever i is at the time of execution.
• When you call each function f(), it looks up the current value of i in its enclosing scope, which is 2.

👉 Result:

2
2
2

✅ How to fix:

You can force the lambda to capture the value of i at the time of definition by using a default argument.

funcs = []
for i in range(3):
    # The default argument captures i's value at definition time
    funcs.append(lambda num=i: print(num))

for f in funcs:
    f()

This trick works because default arguments are evaluated when the function is defined, not when it's called. This will correctly print:

0
1
2

This is a common interview question that tests your understanding of closures, scope, and late binding in Python.

━━━━━━━━━━━━━━━
By: @DataScienceQ ✨