I've spent some sleepless nights and stressful days trying to understand why the latest versions of PHPUnit won't work anymore on any of our dev boxes. It almost drove me mad.
It was like chasing a ghost: you fix one thing, you think everything should now work, you try again, then: SBAM! Another error is bitch-slapping you some truth in your face. Iterate over a dozen times and you'll know how I felt. This was my state until I found about CodeCeption.