public async Task Fail_CostHasBeenRejected_Empty_CostId()
        {
            //Arrange
            var          costId       = Guid.Empty;
            var          costOwnerId  = _costOwnerId;
            var          approvalType = ApprovalType.Brand.ToString();
            const string comments     = "My comments";

            //Act
            bool result = await _emailNotificationService.CostHasBeenRejected(costId, costOwnerId, approvalType, comments);

            //Assert
            result.Should().BeFalse();
            _paperPusherClientMock.Verify(p => p.SendMessage(It.IsAny <EmailNotificationMessage <CostNotificationObject> >()), Times.Never);
        }