I have been using nDumbster on a project to unit test sending emails. It has been an interesting experience working with this little tool. It is a great product but has been out of development for a while and has some issues.
The more I started using nDumbster in test runs, the more I was finding that it wasn’t working so well. I was consistently getting the following exception:
Test method [TestName] threw exception: System.Net.Mail.SmtpException: Failure sending mail. —> System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed.. System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte buffer, Int32 offset, Int32 read, Boolean readLine) System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine) System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller) System.Net.Mail.CheckCommand.Send(SmtpConnection conn, String& response) System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte command, String from) System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) System.Net.Mail.SmtpClient.Send(MailMessage message) System.Net.Mail.SmtpClient.Send(MailMessage message)