aws-sdk-js ReferenceError：您正在尝试在 Jest 环境被拆除后“导入”文件

Question

I need to test whether a pre-signed url to bucket Amazon S3 was returned.

The Jest show the message below when run yarn test :

ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.

      at Object.userAgent (node_modules/aws-sdk/lib/util.js:34:43)
      at HttpRequest.setUserAgent (node_modules/aws-sdk/lib/http.js:111:78)
      at new HttpRequest (node_modules/aws-sdk/lib/http.js:104:10)
      at MetadataService.request (node_modules/aws-sdk/lib/metadata_service.js:93:23)
      at MetadataService.fetchMetadataToken (node_modules/aws-sdk/lib/metadata_service.js:116:10)

That's the test:

index.spec.js

const AWS = require('aws-sdk');

const bucketName = 'bucket';
const key = 'image.png';

describe('Test', () => {
  it('should be able return pre signed url', () => {
    const s3SigV4Client = new AWS.S3({
      signatureVersion: 'v4',
    });
    
    const s3PreSignedUrl = s3SigV4Client.getSignedUrl('getObject', {
      Bucket: bucketName,
      Key: key,
      Expires: 60,
    });

    expect(s3PreSignedUrl);
  });
});

package.json

{
  "name": "test_aws_sdk",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "scripts": {
    "test": "jest"
  },
  "dependencies": {
    "aws-sdk": "^2.807.0"
  },
  "devDependencies": {
    "jest": "^26.6.3"
  }
}

Node.js and Yarn version installed:

$ node -v
v10.19.0
$ yarn -v
1.22.4

There's something I did wrong.

Please can you help me?

Answer 1

After the imports, add jest.useFakeTimers() in your test file:

Example:

const AWS = require('aws-sdk');

jest.useFakeTimers()

const bucketName = 'bucket';
const key = 'image.png';

describe('Test', () => {
  it('should be able return pre signed url', async () => {
    const s3SigV4Client = new AWS.S3({
      signatureVersion: 'v4',
    });
    
    const s3PreSignedUrl = s3SigV4Client.getSignedUrl('getObject', {
      Bucket: bucketName,
      Key: key,
      Expires: 60,
    });

    expect(s3PreSignedUrl);
  });
});

Answer 2

Try mocking instance:

  jest.mock('dynamoose', () => ({
    aws: new class {
      sdk = { config: { update: jest.fn((arg) => arg) } };
    },
    Schema: class { },
    Condition: class { },
    transaction: new class { },
    model: jest.fn(),
    logger: new class { },
    UNDEFINED: new class { },
    THIS: new class { },
    NULL: new class { },
  }));