J How to mock multiple methods call in one function

I have a DeliveryRepository.ts like this:

export class DeliveryRepository {
  constructor() {}

  readonly function1() = async(): Promise<{ delivery?: Delivery }> => {
     // do stuff 1
  }

  readonly function2 = async(): Promise<void> => {
     // do stuff 2
  }

  readonly function3() = async(): Promise<{ delivery?: Delivery }> => {
     // do stuff 3
  }
}

And in my DeliveryService.ts:

import { DeliveryRepository } from '../DeliveryRepository'
export class DeliveryService {
  constructor() {}
  readonly postDelivery = async() : Promise<{ delivery?: Delivery }> => {
     const deliveryRepository = new DeliveryRepository()
     deliveryRepository.function1()
     deliveryRepository.function2()
     deliveryRepository.function3()
     // ...do rest of service
  }
}

and in my DeliveryService.test.ts, I wrote a test for postDelivery function like below:

describe('postDelivery', () => {
   test('postDelivery function', async () => {
     jest.mock('../DeliveryRepository', () => jest.fn()
       .mockImplementation(() => {
          return {
            function1: (): any => {
              return { delivery: undefined }
            }
          }
        })
        .mockImplementation(() => {
          return {
            function2: (): any => {
              return null
            }
          }
        })
        .mockImplementation(() => {
          return {
            function3: (): any => {
              return { delivery: undefined }
            }
          }
        })
   }
}

My problem here is when I run the test, it always throws TypeError: deliveryRepository.function1 is not a function error, if I comment out function1 call in service file, error turned to TypeError: deliveryRepository.function2 is not a function

I don't know what happened with my code, if my service call only one function from repository, the test is passed. I guess that this mockImplementation cannot call multiple functions from one repository, may I wrong, but if you have any idea, please comment to me. Thank you