Problem Descriptoin

Implement unit tests for a shopping cart method using path and loop coverage techniques. The shopping cart functionality handles adding products to a cart collection with the following behaviors:

1. When cart is null, create new collection and add product
2. When cart is empty, add product directly
3. When product exists in cart, increment quantity
4. When product doesn't exist, add new product

Requirements

• Use basic path coverage + simple loop coverage methods
• Implement tests in Java with JUnit framework
• Achieve 100% path and loop coverage
• Use provided test data
• Follow code quality standards

Implementation Classes

Product Class

public class Product {
    private int id;
    private String name;
    private String category;
    private double price;
    private int quantity;

    public Product(int id, String name, String category, double price, int quantity) {
        this.id = id;
        this.name = name;
        this.category = category;
        this.price = price;
        this.quantity = quantity;
    }

    // Getters and setters
    public int getId() { return id; }
    public void setId(int id) { this.id = id; }
    // ... other getters/setters ...
}

CartService Class

public class CartService {
    public List<Product> addToCart(List<Product> cart, Product item) {
        if (cart == null) {
            cart = new ArrayList<>();
            cart.add(item);
        } else {
            boolean exists = false;
            for (Product current : cart) {
                if (current.getId() == item.getId()) {
                    current.setQuantity(current.getQuantity() + item.getQuantity());
                    exists = true;
                    break;
                }
            }
            if (!exists) {
                cart.add(item);
            }
        }
        return cart;
    }
}

Test Data Provider

public class TestData {
    public static List<Product> nullCart = null;
    public static List<Product> emptyCart = new ArrayList<>();
    public static List<Product> populatedCart = new ArrayList<>();

    public static Product phone1 = new Product(1, "Phone", "BrandA", 3000, 2);
    // Additional product definitions
    // ...

    static {
        populatedCart.add(phone1);
        // Add more products to populatedCart
    }
}

Test Implementation

public class CartServiceTest {
    private CartService cartService;

    @Before
    public void setup() {
        cartService = new CartService();
    }

    @Test
    public void testNullCart() {
        List<Product> result = cartService.addToCart(TestData.nullCart, TestData.phone1);
        assertEquals(1, result.size());
        assertEquals(TestData.phone1, result.get(0));
    }

    @Test
    public void testEmptyCart() {
        List<Product> result = cartService.addToCart(TestData.emptyCart, TestData.phone1);
        assertEquals(1, result.size());
        assertEquals(TestData.phone1, result.get(0));
    }

    @Test
    public void testNewProductAddition() {
        Product newProduct = new Product(10, "Tablet", "BrandB", 4000, 1);
        List<Product> result = cartService.addToCart(TestData.populatedCart, newProduct);
        assertTrue(result.contains(newProduct));
    }

    @Test
    public void testExistingProductUpdate() {
        Product existing = TestData.phone1;
        List<Product> result = cartService.addToCart(TestData.populatedCart, existing);
        assertEquals(4, result.get(0).getQuantity());
    }

    // Additional tests for loop coverage
    @Test
    public void testMultipleExistingProducts() {
        // Tests for different positions in the list
        cartService.addToCart(TestData.populatedCart, TestData.phone2);
        cartService.addToCart(TestData.populatedCart, TestData.phone3);
        // Verify quantity updates
    }
}