Before the update my MacBook Pro to MacOs Sierra, the command:
mvn clean install -U
took about 40 sec to run, with several hundreds of tests in
I've had this exact problem (and spent the last 6 hours trying to solve it). My problem was that my HostName wasn't set.
Check that:
sudo scutil --get LocalHostName
Matches:
sudo scutil --get HostName
And if they don't, use:
sudo scutil --set HostName [YOUR_HOST_NAME]
To fix it.