public void CustomerController_ChangeOwner_Exception_AppendsErrorMessageToHeader()
{
_mockCustomerService.Setup(s => s.GetById(It.IsAny <int>())).Throws(new ApplicationException("Oh no!!"));
_controllerWithMockedCustomerService.ChangeOwner(new ChangeCustomerOwnerViewModel());
_mockResponseManager.Verify(v => v.AppendHeader(ModelStateErrorNames.ErrorMessage, It.IsAny <string>()), Times.Once);
}