s3-test.test.js

const s3 = require('./s3') // This is the file where we use aws-sdk's S3 CopyObject method

const mockS3Instance = {
  copyObject: jest.fn().mockReturnThis(),
  promise: jest.fn().mockReturnThis(),
  catch: jest.fn(),
}

jest.mock('aws-sdk', () => {
  return { S3: jest.fn(() => mockS3Instance) }
})

describe('S3', () => {
  it('calls aws-sdk copyObject method with correct parameters, async () => {
      await s3() // This is the function that uses the copyObject method
  
      expect(mockS3Instance.copyObject).toHaveBeenCalledWith({
        Bucket: 'some-bucket',
        CopySource: 'some-bucket/some/path/myfile.json,
        Key: 'some-bucket/some/other/path/myfile.json',
      })
      expect(mockS3Instance.copyObject).toHaveBeenCalledTimes(1)
   })
})