Isolated tests

test_isolated.py

import json
from pathlib import Path
 
import pytest
from mockito import when, mock

from django.urls import reverse
from django.shortcuts import get_object_or_404

from ninja.testing import TestClient

from .views import add_to_cart
from .models import Product, User, CartSchema, CartItem, Product
from .endpoints import api

client = TestClient(api)
schema_file = Path('api_schema.json')

@pytest.fixture
def cart(db):  
    user = User.objects.create_user(username='testuser', password='testpass')
    return Cart.objects.create(user=user)

@pytest.fixture
def product(db):
    return Product.objects.create(name='Test Product', price=10.00)

def test_add_existing_item_to_cart(cart, product, cart_item):
    cart_item = CartItem.objects.create(cart=cart, product=product, quantity=1)
    updated_cart_item = add_item_to_cart(cart, product, 2)
    cart_item.refresh_from_db()
    assert cart_item.quantity == 3
    assert updated_cart_item == cart_item

def test_add_new_item_to_cart(product, cart):
    new_product = Product.objects.create(name='New Product', price=15.00)
    new_cart_item = add_item_to_cart(cart, new_product, 1)
    assert new_cart_item.cart == cart
    assert new_cart_item.product == new_product
    assert new_cart_item.quantity == 1


def test_add_to_cart_endpoint():
    product_mock = mock()
    cart_mock = mock()
    cart_item_mock = mock(quantity=1)
    user_mock = mock(cart=cart_mock)
    request_mock = mock(user=user_mock)

    when(get_object_or_404).called_with(Product, id=1).thenReturn(product_mock)
    when(add_item_to_cart).called_with(cart_mock, product_mock, 1).thenReturn(cart_item_mock)
    response = add_to_cart(request_mock, CartSchema(id=1, quantity=1))

    assert response == {"id": 1, "quantity": 1}

def test_api_schema(get_api_schema):
    if not schema_file.exists():
        pytest.fail(f"API schema is missing, please run ./manage.py dump_schema.")

    current_schema = client.get(reverse("api:schema")).json()
    saved_schema = json.loads(schema_file.read_text())
    if current_schema != saved_schema:
        pytest.fail("API schema has changed. Follow the stability policy.")