I prefer to make sure my implementation does not work only in the lab.
Not sure it is a waste though, since it is greatly helping the development of my C# full bitcoin (+ node server) port that I share with the community.
I'm not downloading gigs of blocks either, just handshaking and disconnecting. (I don't even poll the dns nodes, since I cache their Addr result)
Just wanted to know if such handshake could trigger a black listing.
You could try with testnet?
You could grep the code for DoS and Misbehaving to see if you are doing anything like that?
You could use an internet VPN system to change your IP and try again.
Many nodes might have their ports closed due to router setup etc.
I don't think using the mainnet for unit testing is that great an idea, in general.
Unit tests should be self-contained and fast, so they can complete each time you recompile the code.
You could have a more comprehensive test suite that you run less often. That one could use mainnet, and take longer to run.
It could be part of the series of tests before releasing an update version.
