Cannot send session cookie - headers already sent PHPUnit / Laravel

Question

I have this strange problem when i call the parent::setUp() on my TestCase class for unit test a class when i run phpunit it throw me this error:

Answer 1

One way to handle this in PHPUnit is to send output to stderr instead of stdout as is demonstrated by this answer.

phpunit --stderr

Or by adding stderr="true" in your phpunit.xml as is pointed out in this comment.