我目前正在为一个软件编写单元测试，遇到了一个问题，让我困惑了两天。我有一些使用依赖注入模式完成的服务，我可以很好地模拟这些服务，直到我得到具有DynamoDB.DocumentClient依赖的服务。
我尝试了以下方法，使用这个虚构的服务作为示例：cats.service.ts

import { DynamoDB } from 'aws-sdk';
import { Repository } from 'typeorm';
import { CatDTO, CatEntity} from 'somewhere';
export class CatsService {
    constructor(
        private readonly catRepository: Repository<CatEntity>,
        private readonly clientDB: DynamoDB.DocumentClient,
){}

async findCat (name: string): Promise<CatDTO> {
    try{    
const result = await this.clientDB.query(name).promise();
    return result
} catch(error){
  throw new Error(error) 
}

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问题是：我可以模拟存储库，但不能模拟AWS SDK DynamoDB. DocumentClient。我已经尝试了很多东西，比如jest对模块的手动模拟，jest.mock直接在代码上执行，如here所述，在这里，here和also here。
问题是我尝试了类似于我对typeorm仓库所做的事情，即：

const mockCatRepository = {
    findOne: jest.fn(),
} as unknown as Repository<CatEntity>;

// Here I tried mocking the clientDB DocumentClient in all the ways linked above, such as:
jest.mock('aws-sdk', () => {
  return {
    DynamoDB: {
      DocumentClient: jest.fn(),
    },
  };
});

describe('CatsService typeorm repository dependency example', () => {
    let service: CatsService;
    let mockClientDB: DynamoDB.DocumentClient;
    beforeEach(() => {
        mockClientDB = {} as DynamoDB.DocumentClient;
        mockClientDB.query = jest.fn().mockReturnValue({ promise: jest.fn() });
        service = new CatsService(
            mockCatRepository,
            mockClientDB,
        );
    });

it('should return a cat successfully', async () => {
    const mockInput='Peanut';
// and nothing I tried above I could manage to do something like:
    const mockDynamoReturn = { Items: [{ name: 'Peanut', breed: 'Tabby' }] };
    clientDB.query.promise.mockResolvedValueOnce(mockDynamoReturn)
// since either query or promise don't actually get mocked.
// in this specific case, the following error:

型
error TS2339: Property 'mockResolvedValue' does not exist on type '() => Promise<PromiseResult<QueryOutput, AWSError>>'个
感谢您的时间阅读此！