How to debug env query test

I wrote a custom env query test in c++ base on line trace by object type. But it not seem to work correctly. I placed Env tester in the world and want to find what’s wrong. but I don’t know how to debug the env query test or check the env query test result in level editor. I can only see the ball on the floor(of cause, it doesn’t work as the way I expected) and have no way to check way the result is wrong.
BTW, how to draw debug line of a trace test in env query?