How to mock AWS Cognito CognitoIdentityServiceProvider with Jest?

user_3755578 0
Viewed 3259

I'm trying to write unit test where I need to mock response of method from cognito service - CognitoIdentityServiceProvider

I have the following working code calling the adminInitiateAuth operation

import * from AWS from 'aws-sdk'


const cognito = new AWS.CognitoIdentityServiceProvider();
const response = await cognito.adminInitiateAuth(expectedParams).promise();

// main functionality I want to test

and I want to have a spec where I try to mock this service as prerequisites


const mockResponse = {
  AuthenticationResult: {
    AccessToken: 'expected-token'
  }
}

jest.mock('aws-sdk', () => {
    return {
      CognitoIdentityServiceProvider: {
        adminInitiateAuth: () => {
          return mockResponse;
        }
      }
    }
});

this returns me an error

AWS.CognitoIdentityServiceProvider is not a constructor

How this can not be a constructor? Do you have any ideas how to mock it?

amazon-cognito jestjs express node.js amazon-web-services
3 Answers

I figured it out. It may be useful to someone

jest.mock('aws-sdk', () => {
    return {
      CognitoIdentityServiceProvider: class {
        adminInitiateAuth() {
          return this;
        }

        promise() {
          return Promise.resolve(mockResponse);
        }
      }
    }
});
user_37555780

Here's another way to do it if we want to use spyOn to mock a specific function:

const cognotoIdentityServiceProvider = Object.getPrototypeOf(new AWS.CognitoIdentityServiceProvider());
const stub = jest.spyOn(cognotoIdentityServiceProvider, 'adminDeleteUser').mockReturnValue({
  promise: () => Promise.resolve('bob johnson'),
});
user_35267610

Hope this will help

jest.mock("aws-sdk", () => {
  const cognito = { listUsers: jest.fn() };
  return {
    CognitoIdentityServiceProvider: jest.fn(() => cognito),
    config: {
      update: jest.fn(),
    },
  };
});

const mCognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider();
mCognitoIdentityServiceProvider.listUsers.mockImplementationOnce(() => {
  return {
    promise() {
      return Promise.resolve('your mock data');
    },
  };
});
user_103383980
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