public void TestFormatePhoneNumber() { //Arrange string telephone = "+923336323900"; string dialFrom = "PK"; mockPhoneService.Setup(x => x.FormatePhoneNumberForDisplay(telephone, dialFrom)).Returns(new GenericResponse <ValidatePhoneNumberModel>()); //Act PhoneController phoneController = new PhoneController(mockPhoneService.Object); var result = phoneController.FormatePhoneNumber(telephone, dialFrom); //Assert mockPhoneService.Verify(x => x.ValidatePhoneNumber(telephone, dialFrom), Times.AtMostOnce); }