How to unit test Pop3 Client based on OpenPop.Net

Question

I would like to know if there's a fake (Mock) Mail Server that let us feed our emails (as text or file) and receive them using our application that uses OpenPop.net. Our problem is that there are certain mails (received from various mail servers) that have attachments but when we receive them using our application it says that they don't have any attachments.I would like to be able to test our mail client by changing email header.

Answer 1

Baby POP3 Server looks like it may be suitable for your needs. This is the description from their website:

In the past I have done several projects related to e-mail (POP3/SMTP/IMAP4). One of the problems (at least in my company) is that there are never good test servers available. So that's why I decided to create this simple POP3 server, which doesn’t take many resources and supports most of the standard POP3 commands.

In the configuration description they say it can be used with Microsoft's SMTP server (which is included with Windows), using the SMTP server's mail drop folder as the input folder for the POP3 server.

This means you can email the SMTP server to get test emails into the POP3 server, but in theory you could also just copy test emails directly into that folder.