test(users): 完善users模块测试覆盖

范围：src/core/db/users/
- 添加UsersModule模块配置测试
- 验证模块依赖注入和服务导出
- 确保双模式配置的正确性
- 提升测试覆盖率完整性

src/core/db/users/users.module.spec.ts

@@ -0,0 +1,114 @@
+/**
+ * 用户模块测试套件
+ * 
+ * 功能描述：
+ * - 测试UsersModule的模块配置和依赖注入
+ * - 验证模块导入、提供者和导出的正确性
+ * - 确保用户服务的正确配置
+ * - 测试模块间的依赖关系
+ * 
+ * 测试覆盖范围：
+ * - 模块实例化：模块能够正确创建和初始化
+ * - 依赖注入：所有服务的正确注入
+ * - 服务导出：UsersService的正确导出
+ * - 双模式配置：内存模式和数据库模式的正确配置
+ * 
+ * 最近修改：
+ * - 2026-01-12: 功能新增 - 创建UsersModule测试文件，确保模块配置测试覆盖 (修改者: moyin)
+ * 
+ * @author moyin
+ * @version 1.0.0
+ * @since 2026-01-12
+ * @lastModified 2026-01-12
+ */
+
+import { Test, TestingModule } from '@nestjs/testing';
+import { ConfigService } from '@nestjs/config';
+import { UsersModule } from './users.module';
+import { UsersService } from './users.service';
+import { UsersMemoryService } from './users_memory.service';
+
+describe('UsersModule', () => {
+  let module: TestingModule;
+  let usersService: any;
+
+  beforeEach(async () => {
+    const mockConfigService = {
+      get: jest.fn((key: string, defaultValue?: any) => {
+        switch (key) {
+          case 'DATABASE_MODE':
+            return 'memory';
+          default:
+            return defaultValue;
+        }
+      }),
+    };
+
+    module = await Test.createTestingModule({
+      imports: [UsersModule.forMemory()],
+    })
+      .overrideProvider(ConfigService)
+      .useValue(mockConfigService)
+      .compile();
+
+    usersService = module.get<UsersService>('UsersService');
+  });
+
+  afterEach(async () => {
+    if (module) {
+      await module.close();
+    }
+  });
+
+  it('should be defined', () => {
+    expect(module).toBeDefined();
+  });
+
+  describe('Service Providers', () => {
+    it('should provide UsersService', () => {
+      expect(usersService).toBeDefined();
+      expect(usersService).toBeInstanceOf(UsersMemoryService);
+    });
+  });
+
+  describe('Module Dependencies', () => {
+    it('should import required modules', () => {
+      expect(module).toBeDefined();
+      expect(usersService).toBeDefined();
+    });
+
+    it('should not have circular dependencies', () => {
+      expect(module).toBeDefined();
+    });
+  });
+
+  describe('Module Exports', () => {
+    it('should export UsersService', () => {
+      expect(usersService).toBeDefined();
+      expect(usersService).toBeInstanceOf(UsersMemoryService);
+    });
+
+    it('should make UsersService available for injection', () => {
+      const service = module.get('UsersService');
+      expect(service).toBe(usersService);
+    });
+  });
+
+  describe('Dynamic Module Configuration', () => {
+    it('should create memory module correctly', () => {
+      const memoryModule = UsersModule.forMemory();
+      expect(memoryModule).toBeDefined();
+      expect(memoryModule.module).toBe(UsersModule);
+      expect(memoryModule.providers).toBeDefined();
+      expect(memoryModule.exports).toBeDefined();
+    });
+
+    it('should create database module correctly', () => {
+      const databaseModule = UsersModule.forDatabase();
+      expect(databaseModule).toBeDefined();
+      expect(databaseModule.module).toBe(UsersModule);
+      expect(databaseModule.providers).toBeDefined();
+      expect(databaseModule.exports).toBeDefined();
+    });
+  });
+});