public void Send_Message_With_Attachment(string fileFormat) { var message = GetTestMessage(fileFormat); _client.Send(message); Thread.Sleep(WaitForMessageSentTimeout); var messagesSent = _client.GetMessages(new SubjectFilter(message.Subject)); messagesSent.Should().HaveCount(1); messagesSent.Select(msg => msg.Attachments.First().Data).Should() .AllBeEquivalentTo(message.Attachments.First().Data, "Attachment data did not match"); }