flyer-crawler.projectium.com/src/services/db/deals.db.test.ts

// src/services/db/deals.db.test.ts
import { describe, it, expect, vi, beforeEach } from 'vitest';
import { DealsRepository } from './deals.db';
import type { WatchedItemDeal } from '../../types';

// Un-mock the module we are testing to ensure we use the real implementation.
vi.unmock('./deals.db');

// Mock the logger to prevent console output during tests
vi.mock('../logger.server', () => ({
  logger: {
    info: vi.fn(),
    warn: vi.fn(),
    error: vi.fn(),
    debug: vi.fn(),
  },
}));
import { logger as mockLogger } from '../logger.server';

describe('Deals DB Service', () => {
  // Import the Pool type to use for casting the mock instance.
  let dealsRepo: DealsRepository;
  const mockDb = {
    query: vi.fn()
  };

  beforeEach(() => {
    vi.clearAllMocks();

    mockDb.query.mockReset()

    // Instantiate the repository with the minimal mock db for each test
    dealsRepo = new DealsRepository(mockDb);
  });

  describe('findBestPricesForWatchedItems', () => {
    it('should execute the correct query and return deals', async () => {
      // Arrange
      const mockDeals: WatchedItemDeal[] = [
        {
          master_item_id: 1,
          item_name: 'Apples',
          best_price_in_cents: 199,
          store_name: 'Good Food',
          flyer_id: 10,
          valid_to: '2025-12-25',
        },
        {
          master_item_id: 2,
          item_name: 'Milk',
          best_price_in_cents: 350,
          store_name: 'Super Grocer',
          flyer_id: 11,
          valid_to: '2025-12-24',
        },
      ];
      mockDb.query.mockResolvedValue({ rows: mockDeals });

      // Act
      const result = await dealsRepo.findBestPricesForWatchedItems('user-123', mockLogger);

      // Assert
      expect(result).toEqual(mockDeals);
      expect(mockDb.query).toHaveBeenCalledWith(
        expect.stringContaining('FROM flyer_items fi'),
        ['user-123'],
      );
      expect(mockLogger.debug).toHaveBeenCalledWith(
        { userId: 'user-123' },
        'Finding best prices for watched items.',
      );
    });

    it('should return an empty array if no deals are found', async () => {
      mockDb.query.mockResolvedValue({ rows: [] });

      const result = await dealsRepo.findBestPricesForWatchedItems(
        'user-with-no-deals',
        mockLogger,
      );

      expect(result).toEqual([]);
    });

    it('should throw a generic error if the database query fails', async () => {
      const dbError = new Error('DB Connection Error');
      mockDb.query.mockRejectedValue(dbError);

      await expect(dealsRepo.findBestPricesForWatchedItems('user-1', mockLogger)).rejects.toThrow(
        'Failed to find best prices for watched items.',
      );
      expect(mockLogger.error).toHaveBeenCalledWith(
        { err: dbError, userId: 'user-1' },
        'Database error in findBestPricesForWatchedItems',
      );
    });
  });
});