public void TryModifyAttachment_Test()
        {
            _controller.Request       = new HttpRequestMessage();
            _controller.Configuration = new System.Web.Http.HttpConfiguration();

            AttachmentDTO attachmentDTO = new AttachmentDTO
            {
                Id           = 69,
                AssessmentId = 1109,
                Name         = "Lerman J., Miller R. - Programming Entity Framework. Code First - 2011.pdf",
                UniqueName   = "~/Files/Lerman J., Miller R. - Programming Entity Framework. Code First - 2011.pdf",
                Comment      = "Interesting book.",
                Size         = 6622819
            };

            HttpResponseMessage response = _controller.ModifyAttachment(attachmentDTO);
        }