javascript - 如何在 Typescript 中模拟 Cognito 响应

Question

定义class CognitoPool后，将其保存为cognitoPool.ts脚本:

const AWS = require('aws-sdk');
import { CognitoIdentityServiceProvider } from 'aws-sdk';
import {ListUsersRequest, ListUsersResponse} from 'aws-sdk/clients/cognitoidentityserviceprovider';

export class CognitoPool {
  private identityService: CognitoIdentityServiceProvider;

  constructor(identityService: CognitoIdentityServiceProvider) {    
    this.identityService = identityService;
  }

  async listCognitoUsers(poolID: string, sub: string): Promise<ListUsersResponse> {

    let params = {
      UserPoolId: poolID,
      Filter: `sub="${sub}"`
    } as ListUsersRequest;

    let res: ListUsersResponse = await this.identityService.listUsers(params).promise();
    return res;
  }
}

export default new CognitoPool(new AWS.CognitoIdentityServiceProvider());

我继续编写测试脚本:

const AWS = require('aws-sdk');
import sinon, { stubObject } from 'ts-sinon'
import { CognitoIdentityServiceProvider, AWSError } from 'aws-sdk';
import { PromiseResult } from 'aws-sdk/lib/request';
import { CognitoPool } from './cognitoPool';


describe('Testing', () => {

  const identityService = new AWS.CognitoIdentityServiceProvider();

  const stub = stubObject(identityService);

  const cognitoPool = new CognitoPool(stub);

  it('Test 01', async () => {

    let mockData = {
      Users: []
    } as unknown as PromiseResult<any, AWSError>;
    
    stub.listUsers.returns(mockData); 

    let result = await cognitoPool.listCognitoUsers('poolId-123', 'sub-123');

  })

})

mockData 将由 identityService.listUsers() 作为 as PromiseResult 返回:

    let mockData = {
      Users: []
    } as unknown as PromiseResult<any, AWSError>;

但是测试脚本运行时出现错误:

TypeError: this.identityService.listUsers(...).promise is not a function

有办法避免这个错误吗？

Answer 1

PromiseResult 是一个包含 .promise 作为函数的对象。然后，当您想要模拟函数以返回 PromiseResult 时，模拟数据应该是像 PromiseResult 这样的对象。

在您的情况下，mockData 应该是:

const mockData = {
  promise: () => Promise.resolve({ Users: [] }),
} as unknown as PromiseResult<any, AWSError>;