public string Transfer( Account debitAccount, Account creditAccount, decimal amount, string motif ) { MGuid.NewGuid = () => new Guid("64d80a10-4f21-4acb-9d3d-0332e68c4394"); PexAssume.IsNotNull(debitAccount); PexAssume.IsNotNull(creditAccount); PexAssume.IsTrue(creditAccount != debitAccount); var repository = new SIRepository(); var operationRepository = new SIOperationRepository(); var operationCreator = new OperationDtoCreator(); //act var operationServices = new OperationServices(operationRepository, repository, operationCreator); operationServices.Transfer(debitAccount, creditAccount, amount, motif); string result = operationServices.Transfer(debitAccount, creditAccount, amount, motif); PexAssert.IsNotNullOrEmpty(result); return(result); }