Tested on OS X 10.9.
Run:
npm install
./node_modules/karma/bin/karma start
Connect a few browsers to http://localhost:9876/.
In a new terminal, run:
./node_modules/karma/bin/karma run
This should succeed. Now restart the Karma server in the first terminal using Ctrl-C and re-running the start command. I'd expect the browsers to get reconnected automatically (as seen in http://www.letscodejavascript.com/v3/episodes/espresso/134), but they don't reconnect.