inventory-barcode-system/__tests__/Product.test.js

const Product = require('../models/Product');
const database = require('../models/database');

describe('Product Model', () => {
  beforeAll(async () => {
    // Initialize database for testing
    database.initialize();
  });

  afterAll(() => {
    // Close database connection
    database.close();
  });

  beforeEach(() => {
    // Clear items table before each test
    const db = database.getDatabase();
    db.exec('DELETE FROM items');
  });

  describe('Validation', () => {
    test('should validate required fields', () => {
      const product = new Product();
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Product name is required');
    });

    test('should validate product name length', () => {
      const product = new Product({ name: 'a'.repeat(256) });
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Product name must be less than 255 characters');
    });

    test('should validate quantity is non-negative number', () => {
      const product = new Product({ name: 'Test Product', quantity: -1 });
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Quantity must be a non-negative number');
    });

    test('should validate min_stock_level is non-negative number', () => {
      const product = new Product({ name: 'Test Product', min_stock_level: -1 });
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Minimum stock level must be a non-negative number');
    });

    test('should validate category length', () => {
      const product = new Product({ 
        name: 'Test Product', 
        category: 'a'.repeat(101) 
      });
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Category must be less than 100 characters');
    });

    test('should validate unit length', () => {
      const product = new Product({ 
        name: 'Test Product', 
        unit: 'a'.repeat(21) 
      });
      const validation = product.validate();
      
      expect(validation.isValid).toBe(false);
      expect(validation.errors).toContain('Unit must be less than 20 characters');
    });

    test('should pass validation with valid data', () => {
      const product = new Product({
        name: 'Test Product',
        description: 'A test product',
        category: 'Electronics',
        quantity: 10,
        unit: 'pieces',
        barcode: '123456789',
        location: 'A1-B2',
        min_stock_level: 5
      });
      
      const validation = product.validate();
      expect(validation.isValid).toBe(true);
      expect(validation.errors).toHaveLength(0);
    });
  });

  describe('Database Operations', () => {
    test('should save new product to database', async () => {
      const productData = {
        name: 'Test Product',
        description: 'A test product',
        category: 'Electronics',
        quantity: 10,
        unit: 'pieces',
        barcode: '123456789',
        location: 'A1-B2',
        min_stock_level: 5
      };
      
      const product = new Product(productData);
      await product.save();
      
      expect(product.id).toBeDefined();
      expect(product.id).toBeGreaterThan(0);
    });

    test('should update existing product', async () => {
      // First create a product
      const product = new Product({
        name: 'Test Product',
        quantity: 10
      });
      await product.save();
      
      // Update the product
      product.name = 'Updated Product';
      product.quantity = 20;
      await product.save();
      
      // Verify the update
      const updatedProduct = await Product.findById(product.id);
      expect(updatedProduct.name).toBe('Updated Product');
      expect(updatedProduct.quantity).toBe(20);
    });

    test('should find product by ID', async () => {
      const product = new Product({
        name: 'Test Product',
        barcode: '123456789'
      });
      await product.save();
      
      const foundProduct = await Product.findById(product.id);
      expect(foundProduct).toBeDefined();
      expect(foundProduct.name).toBe('Test Product');
      expect(foundProduct.barcode).toBe('123456789');
    });

    test('should find product by barcode', async () => {
      const product = new Product({
        name: 'Test Product',
        barcode: '123456789'
      });
      await product.save();
      
      const foundProduct = await Product.findByBarcode('123456789');
      expect(foundProduct).toBeDefined();
      expect(foundProduct.name).toBe('Test Product');
    });

    test('should return null when product not found', async () => {
      const foundProduct = await Product.findById(999);
      expect(foundProduct).toBeNull();
    });

    test('should find all products', async () => {
      // Create multiple products
      const product1 = new Product({ name: 'Product 1', category: 'Electronics' });
      const product2 = new Product({ name: 'Product 2', category: 'Books' });
      
      await product1.save();
      await product2.save();
      
      const allProducts = await Product.findAll();
      expect(allProducts).toHaveLength(2);
    });

    test('should filter products by category', async () => {
      const product1 = new Product({ name: 'Product 1', category: 'Electronics' });
      const product2 = new Product({ name: 'Product 2', category: 'Books' });
      
      await product1.save();
      await product2.save();
      
      const electronicsProducts = await Product.findAll({ category: 'Electronics' });
      expect(electronicsProducts).toHaveLength(1);
      expect(electronicsProducts[0].name).toBe('Product 1');
    });

    test('should delete product by ID', async () => {
      const product = new Product({ name: 'Test Product' });
      await product.save();
      
      const deleted = await Product.deleteById(product.id);
      expect(deleted).toBe(true);
      
      const foundProduct = await Product.findById(product.id);
      expect(foundProduct).toBeNull();
    });

    test('should handle unique barcode constraint', async () => {
      const product1 = new Product({ name: 'Product 1', barcode: '123456789' });
      await product1.save();
      
      const product2 = new Product({ name: 'Product 2', barcode: '123456789' });
      
      await expect(product2.save()).rejects.toThrow('A product with this barcode already exists');
    });

    test('should throw validation error when saving invalid product', async () => {
      const product = new Product({ quantity: -1 }); // Invalid: no name and negative quantity
      
      await expect(product.save()).rejects.toThrow('Validation failed');
    });
  });

  describe('JSON Serialization', () => {
    test('should convert product to JSON', () => {
      const productData = {
        id: 1,
        name: 'Test Product',
        description: 'A test product',
        category: 'Electronics',
        quantity: 10,
        unit: 'pieces',
        barcode: '123456789',
        qr_code: 'QR123',
        location: 'A1-B2',
        min_stock_level: 5,
        created_at: '2023-01-01 00:00:00',
        updated_at: '2023-01-01 00:00:00'
      };
      
      const product = new Product(productData);
      const json = product.toJSON();
      
      expect(json).toEqual(productData);
    });
  });
});