Ladies and gentlemen, the situation is simple.
So simple, in fact, that I can sum it up in three sentences:
I made a game for the ongoing MAGS, it will be beta-ready by the 15th of July.
I need someone to test it until either the game breaks, or the person doing the testing breaks.
I have to finish the project by the 20th of July, so time is of the essence.
I can give it a go, am looking forward to play it anyway. (nod)
I didn't test games before but would like to try with this one.
Is there any system to it?
The system I use: Play like you would normally play a game, take notes of everything you notice (notepad is a good option to keep the notes in), being bugs, missing interactions, suggestions, etc. Once you finish the game, start it again and try to break it, by trying everything you can think of doing. Take notes... report notes to game owner when you're done or as you test (in case of serious bugs that will crash or are game breaking).