Refactor tests to use mockClient for database interactions, improve error handling, and enhance modal functionality

- Updated personalization.db.test.ts to use mockClient for query calls in addWatchedItem tests.
- Simplified error handling in shopping.db.test.ts, ensuring clearer error messages.
- Added comprehensive tests for VoiceAssistant component, including rendering and interaction tests.
- Introduced useModal hook with tests to manage modal state effectively.
- Created deals.db.test.ts to test deals repository functionality with mocked database interactions.
- Implemented error handling tests for custom error classes in errors.db.test.ts.
- Developed googleGeocodingService.server.test.ts to validate geocoding service behavior with mocked fetch.

src/services/db/deals.db.test.ts

@@ -0,0 +1,64 @@
+// src/services/db/deals.db.test.ts
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { mockPoolInstance } from '../../tests/setup/tests-setup-unit';
+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', () => {
+  let dealsRepo: DealsRepository;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    // Instantiate the repository with the mock pool for each test
+    dealsRepo = new DealsRepository(mockPoolInstance as any);
+  });
+
+  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' },
+      ];
+      mockPoolInstance.query.mockResolvedValue({ rows: mockDeals });
+
+      // Act
+      const result = await dealsRepo.findBestPricesForWatchedItems('user-123', mockLogger);
+
+      // Assert
+      expect(result).toEqual(mockDeals);
+      expect(mockPoolInstance.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 () => {
+      mockPoolInstance.query.mockResolvedValue({ rows: [] });
+
+      const result = await dealsRepo.findBestPricesForWatchedItems('user-with-no-deals', mockLogger);
+
+      expect(result).toEqual([]);
+    });
+
+    it('should re-throw the error if the database query fails', async () => {
+      const dbError = new Error('DB Connection Error');
+      mockPoolInstance.query.mockRejectedValue(dbError);
+
+      await expect(dealsRepo.findBestPricesForWatchedItems('user-1', mockLogger)).rejects.toThrow(dbError);
+      expect(mockLogger.error).toHaveBeenCalledWith({ err: dbError }, 'Database error in findBestPricesForWatchedItems');
+    });
+  });
+});