It seems that tests fail because of lots of child process with mocha-phantom which we run for every spec.
18:59:38.177 - error: Tests failed killed=false, code=255, signal=null
Error: Command failed:
at ChildProcess.exithandler (child_process.js:637:15)
at ChildProcess.EventEmitter.emit (events.js:98:17)
at maybeClose (child_process.js:735:16)
at Socket.<anonymous> (child_process.js:948:11)
at Socket.EventEmitter.emit (events.js:95:17)
at Pipe.close (net.js:466:12)
It seems that tests fail because of lots of child process with mocha-phantom which we run for every spec.