Xdebug configuration is a somewhat temperamental issue -- the details depend on the IDE, the PHP build, host OS, target application, test suite, etc. Providing a good answer to this is tricky -- e.g. I could describe my configuration (Mac OS X, PHPStorm 2016.2, MAMP 3.4, PHP 5.4, buildkit/dmaster), but the odds are that most people reading it will need ...
Here are the steps/complete set of screenshots of a configuration that now works for me:
1) from command line ensure you can run buildkit -> civibuild
$ civibuild create dmaster --url http://d47.localhost --admin-pass mypass
2) from command line ensure you can run tests - that all is working properly
karins-macbook-pro:civicrm sysadmin$ pwd
You must enable the ‘Enable multiple bulk email address for a contact’ option from CiviMail component settings.
Administer > CiviMail > CiviMail component settings