feat: enhance cart API to return sorted items and total price calcula…

…tion

backend/app/routes/cart.py

@@ -10,21 +10,31 @@
 @token_required
 def get_cart(current_user):
     try:
-        cart_items = Cart.query.filter_by(user_id=current_user.id).all()
-        return jsonify(
-            [
-                {
-                    "id": item.id,
-                    "product": {
-                        "id": item.product_id,
-                        "name": Product.query.get(item.product_id).name,
-                        "price": Product.query.get(item.product_id).price,
-                    },
-                    "quantity": item.quantity,
-                }
-                for item in cart_items
-            ]
-        )
+        cart_items = Cart.query.filter_by(user_id=current_user.id).order_by(Cart.id).all()
+
+        items = []
+        total = 0
+
+        for item in cart_items:
+            product = Product.query.get(item.product_id)
+            item_total = product.price * item.quantity
+            total += item_total
+
+            items.append({
+                "id": item.id,
+                "product": {
+                    "id": item.product_id,
+                    "name": product.name,
+                    "price": product.price,
+                },
+                "quantity": item.quantity,
+            })
+
+        return jsonify({
+            "items": items,
+            "total": total
+        })
+
     except Exception as e:
         return jsonify(
             {"message": "Failed to fetch cart items", "details": str(e)}

backend/tests/test_cart.py

@@ -1,15 +1,19 @@
 import pytest
 from flask import json
+from app.models import Product, Cart
 
 
 def test_get_cart(client, auth_headers, test_cart):
     """Test getting user's cart items."""
     response = client.get("/api/cart/", headers=auth_headers)
     assert response.status_code == 200
     data = json.loads(response.data)
-    assert len(data) == 1
-    assert data[0]["quantity"] == test_cart.quantity
-    assert data[0]["product"]["id"] == test_cart.product_id
+    assert "items" in data
+    assert "total" in data
+    assert len(data["items"]) == 1
+    assert data["items"][0]["quantity"] == test_cart.quantity
+    assert data["items"][0]["product"]["id"] == test_cart.product_id
+    assert data["total"] == test_cart.quantity * Product.query.get(test_cart.product_id).price
 
 
 def test_add_to_cart(client, auth_headers, test_products):
@@ -83,3 +87,58 @@ def test_cart_unauthorized(client):
     """Test accessing cart without authentication."""
     response = client.get("/api/cart/")
     assert response.status_code == 401
+
+def test_get_cart_order_and_total(client, auth_headers, test_user, test_products, db_session):
+    """Test cart sorting by ID and total price calculation."""
+
+    cart_items = [
+        Cart(user_id=test_user.id, product_id=test_products[0].id, quantity=2),
+        Cart(user_id=test_user.id, product_id=test_products[0].id, quantity=1),
+        Cart(user_id=test_user.id, product_id=test_products[1].id, quantity=3),
+    ]
+
+    for item in cart_items:
+        db_session.add(item)
+    db_session.commit()
+
+    expected_total = (
+        test_products[0].price * 2 +
+        test_products[0].price * 1 +
+        test_products[1].price * 3
+    )
+
+    response = client.get("/api/cart/", headers=auth_headers)
+    assert response.status_code == 200
+    data = json.loads(response.data)
+
+    assert "items" in data
+    assert "total" in data
+
+    items = data["items"]
+    assert len(items) == 3
+    assert items[0]["product"]["id"] == test_products[0].id
+    assert items[1]["product"]["id"] == test_products[0].id
+    assert items[2]["product"]["id"] == test_products[1].id
+
+    assert data["total"] == expected_total
+
+    response = client.put(
+        f"/api/cart/update/{items[1]['id']}", 
+        headers=auth_headers, 
+        json={"quantity": 5}
+    )
+    assert response.status_code == 200
+
+    response = client.get("/api/cart/", headers=auth_headers)
+    data = json.loads(response.data)
+
+    assert data["items"][0]["product"]["id"] == test_products[0].id
+    assert data["items"][1]["product"]["id"] == test_products[0].id
+    assert data["items"][2]["product"]["id"] == test_products[1].id
+
+    new_expected_total = (
+        test_products[0].price * 2 +
+        test_products[0].price * 5 +
+        test_products[1].price * 3
+    )
+    assert data["total"] == new_expected_total