feat: add Jest testing framework and implement unit tests for configuration and service logic

tests/discord.service.test.ts

@@ -0,0 +1,68 @@
+import { DiscordService } from '../src/services/discord.service';
+import { Client } from 'discord.js';
+
+// Mock discord.js
+jest.mock('discord.js', () => ({
+  Client: jest.fn().mockImplementation(() => ({
+    isReady: jest.fn(),
+    login: jest.fn(),
+    on: jest.fn(),
+    once: jest.fn(),
+    destroy: jest.fn(),
+  })),
+  GatewayIntentBits: {
+    Guilds: 'GUILDS',
+  },
+}));
+
+// Mock other dependencies
+jest.mock('../src/config/config');
+jest.mock('../src/config/storage');
+jest.mock('../src/services/commands.service');
+jest.mock('../src/services/uptime-kuma.service');
+
+describe('DiscordService', () => {
+  let discordService: DiscordService;
+  let mockClient: jest.Mocked<Client>;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    
+    // Get the mocked client instance
+    mockClient = new Client({ intents: [] }) as jest.Mocked<Client>;
+    
+    discordService = new DiscordService();
+  });
+
+  test('should create Discord client with correct intents', () => {
+    expect(Client).toHaveBeenCalledWith({
+      intents: ['GUILDS'],
+    });
+  });
+
+  test('should return client instance', () => {
+    const client = discordService.getClient();
+    expect(client).toBeDefined();
+  });
+
+  test('should return connection status', () => {
+    // Get the actual client from the service
+    const client = discordService.getClient();
+    
+    // Test when client is ready
+    (client as any).isReady = jest.fn().mockReturnValue(true);
+    expect(discordService.isConnected()).toBe(true);
+
+    // Test when client is not ready
+    (client as any).isReady = jest.fn().mockReturnValue(false);
+    expect(discordService.isConnected()).toBe(false);
+  });
+
+  test('should set uptime kuma service', () => {
+    const mockUptimeKumaService = {} as any;
+    
+    expect(() => {
+      discordService.setUptimeKumaService(mockUptimeKumaService);
+    }).not.toThrow();
+  });
+});