Testing (pytest) ও Code Quality

uv add --dev pytest

# src/shop/pricing.py
def apply_discount(price: int, percent: int) -> int:
    if not 0 <= percent <= 100:
        raise ValueError("percent ০ থেকে ১০০ এর মধ্যে হতে হবে")
    return price - price * percent // 100

# tests/test_pricing.py
import pytest
from shop.pricing import apply_discount


def test_normal_discount():
    assert apply_discount(1000, 10) == 900


def test_zero_discount():
    assert apply_discount(1000, 0) == 1000


def test_full_discount():
    assert apply_discount(1000, 100) == 0


def test_invalid_percent_raises():
    with pytest.raises(ValueError, match="০ থেকে ১০০"):
        apply_discount(1000, 150)

uv run pytest            # সব test
uv run pytest -v         # প্রতিটা test এর নাম সহ
uv run pytest -x         # প্রথম ব্যর্থ test এ থামো
uv run pytest -k discount   # নামে "discount" আছে এমন test

def test_cart_total_with_discount():
    # Arrange: প্রস্তুতি
    cart = Cart()
    cart.add(Item("Burger", 25000), qty=2)
    cart.add(Item("Coke", 4000))

    # Act: আসল কাজ
    total = cart.total(coupon="EID10")

    # Assert: যাচাই
    assert total == 48600

@pytest.mark.parametrize(
    ("price", "percent", "expected"),
    [
        (1000, 10, 900),
        (1000, 0, 1000),
        (1000, 100, 0),
        (999, 33, 670),      # ভাগের পর পূর্ণসংখ্যা
        (1, 50, 1),          # ছোট সংখ্যায় rounding
    ],
)
def test_apply_discount(price, percent, expected):
    assert apply_discount(price, percent) == expected

# tests/conftest.py  ← এই file এর fixture সব test file পায়
import pytest
from shop.cart import Cart, Item


@pytest.fixture
def burger() -> Item:
    return Item("Burger", 25000)


@pytest.fixture
def cart_with_items(burger) -> Cart:          # fixture অন্য fixture ব্যবহার করতে পারে
    cart = Cart()
    cart.add(burger, qty=2)
    return cart


# tests/test_cart.py
def test_total(cart_with_items):
    assert cart_with_items.total() == 50000

def test_remove(cart_with_items, burger):
    cart_with_items.remove(burger)
    assert cart_with_items.total() == 0

@pytest.fixture
def temp_store(tmp_path):                 # tmp_path: pytest এর দেওয়া অস্থায়ী folder
    store = JsonStore(tmp_path / "data.json")
    yield store                            # test এখানে চলে
    store.close()                          # test শেষে পরিষ্কার

class FakeNotifier:
    def __init__(self) -> None:
        self.sent: list[tuple[str, str]] = []

    def send(self, to: str, message: str) -> None:
        self.sent.append((to, message))       # পাঠায় না, শুধু মনে রাখে


def test_order_sends_confirmation():
    notifier = FakeNotifier()
    service = OrderService(notifier=notifier)

    service.place(Order(id=1, customer="01711111111"))

    assert notifier.sent == [("01711111111", "আপনার order নেওয়া হয়েছে")]

def test_weather_fallback(monkeypatch):
    def fake_get(*args, **kwargs):
        raise httpx.TimeoutException("timeout")

    monkeypatch.setattr(httpx.Client, "get", fake_get)
    assert get_temperature_or_default("Dhaka") == 30.0

uv add --dev pytest-asyncio

import pytest

@pytest.mark.asyncio
async def test_fetch_user():
    user = await fetch_user(1)
    assert user["id"] == 1

uv add --dev pytest-cov
uv run pytest --cov=src --cov-report=term-missing

Name                     Stmts   Miss  Cover   Missing
------------------------------------------------------
src/shop/pricing.py         12      0   100%
src/shop/cart.py            40      6    85%   51-56

uv run ruff format .          # code সাজাও
uv run ruff check .           # সম্ভাব্য bug আর খারাপ অভ্যাস খোঁজো
uv run ruff check --fix .     # যেগুলো নিজে ঠিক করা যায়, ঠিক করো

[tool.ruff]
line-length = 100

[tool.ruff.lint]
select = ["E", "F", "I", "B", "UP", "SIM", "ASYNC", "S"]
# E,F: মৌলিক ভুল | I: import সাজানো | B: সাধারণ bug (mutable default ইত্যাদি)
# UP: পুরনো syntax আধুনিক করা | SIM: সহজ করা | ASYNC: async এর ভুল | S: security

uv run pyright

uv add --dev pre-commit

# .pre-commit-config.yaml
repos:
  - repo: local
    hooks:
      - id: ruff-format
        name: ruff format
        entry: uv run ruff format
        language: system
        types: [python]
      - id: ruff-check
        name: ruff check
        entry: uv run ruff check --fix
        language: system
        types: [python]
      - id: pyright
        name: pyright
        entry: uv run pyright
        language: system
        types: [python]
        pass_filenames: false

uv run pre-commit install