MyService.Get C# (CSharp) Method

      public MyModel Get(string id)
      {
        // Work
      }
    }

        public void Test_Get_Entity_Doesnt_Exist()
        {
            const int id = 5;

            var repositoryMock = TestHelper.SetupMock <IListRepository <MyEntity> >();
            var messengerMock  = TestHelper.SetupMock <IMessenger>();

            repositoryMock.Setup(x => x.GetById(id)).Returns(new ErrorResult <MyEntity>(""));

            var service = new MyService(repositoryMock.Object);

            service.Messenger = messengerMock.Object;
            var result = service.Get(id);

            Assert.IsInstanceOf <ErrorResult <MyModel> >(result);
            Assert.IsFalse(result.IsSuccess);
            Assert.IsFalse(string.IsNullOrEmpty(result.ErrorMessage));

            repositoryMock.VerifyAll();
            messengerMock.VerifyAll();
        }