Is Run Caja Tester button working? I tried it and received js alert with "failure [object Object]"

Are you still having problems with this?

Either way, I'll check into it. 

Yeah, this issue is still happening to me. Also, as other posts have mentioned, even if I have very basic js code, the system still complains "Your source contains errors. Please correct and try again" and when I clicked on "Show messages", there's nothing to see