Hi! When I try to run any test (also standard tests and my own) I get this error:
What is problem?
I think this is a glitch. You get this message when you first populate the tests list. if you exit and re-enter the page or similar it starts to work.
Debug the error, you will get the solution.
It is tempting, but maybe not helpful, to say that the problem is probably exactly what the error message tells you. Have you checked what function you use on the line in question and tried to change the value to blank?