In my team we were having some problems on the display of some tests.
Some of them were outputting newlines and we were not able to redirect the output and show a clean phpunit test output.
The tests execution was like this:
It was very disturbing, that everytime we execute our tests that newline was there to annoy us.
So after a little research I found out that there was an interface in our application that was closed with a ?> (php close tag) and after that some new lines.
That was causing our tests to be output in a wrong way, so I just delete that tag and everything was fine again. :)