public void AddAttachment_VariationWithContentID_AddsAttachmentToAttachmentsListWithProvidedContentID() { //---------------Set up test pack------------------- using (var email = CreateWithRandomRecipientAndSender()) { var fileName = RandomValueGen.GetRandomString(); var data = RandomValueGen.GetRandomBytes(); var mimeType = RandomValueGen.GetRandomMIMEType(); var contentID = RandomValueGen.GetRandomAlphaNumericString(); //---------------Assert Precondition---------------- Assert.AreEqual(0, email.Attachments.Count); //---------------Execute Test ---------------------- email.AddAttachment(fileName, data, mimeType, contentID); //---------------Test Result ----------------------- var attachment = email.Attachments.FirstOrDefault(a => a.Name == fileName && a.MIMEType == mimeType && a.ContentID == contentID); Assert.IsNotNull(attachment); CollectionAssert.AreEqual(data, attachment.Data); var message = email.CreateMessage(); var actual = message.Attachments.First(); Assert.IsTrue(actual.ContentDisposition.Inline); Assert.AreEqual(actual.ContentDisposition.DispositionType, DispositionTypeNames.Inline); } }