Most Helpful Guy
I don't "test" my girlfriends loyalty, either its there or its not, time will tell and if and when such a time comes, that will be the time I will address the issue. I don't think its common for guys to test their girlfriends. I believe its only common with those who have jealousy or esteem issues or just plain issues of insecurity.
Relationships are based on trust. Without trust, there can't be a relationship. If he doesn't trust her, or has trust issues in general, he really doesn't need to be in a relationship. She may find it sweet that he "tests" her, but most people, both men and women, would find it offensive and a lot of people won't go stand for it. Basically its a mind game and shouldn't be played with the one you love.
Furthermore, just because she "passes" certain tests, doesn't always mean that she will be faithful. Perhaps the test or test subject wasn't a strong enough motivational factor to compel her to want to cheat. If its in her nature to cheat, then its obvious she will cheat.
He definitely has confidence as well as esteem and jealousy issues, possibly from experiences in past relationships and he's carrying that baggage into his current relationship which is unfair to her. If she is indeed a faithful woman by character, then its a terrible injustice for her to carry the burden of what his previous girlfriends did. Everyone is different and deserves to be treated with respect and given the benefit of the doubt until proved otherwise.
Another motivation behind his behavior could be he's testing her and placing the focus on her because he actually is the one with fidelity issues and he may be questioning her fidelity or loyalty to him to take thee focus off his behavior. This is a common ploy by those who want to make sure that the person they're with is too busy to focus on defending themselves that they can't clearly see what their partner is doing.
Additionally, chronic drug use often clouds judgment, creates paranoia, and causes irrational thinking, which no doubt was contributing to his problem. Its good that he quit (if he really did quit) but now he should focus on being a better person all the way around and not just in the relationship.
Either way this guy spells loser and she really needs to sit down and talk with him and try to resolve this issue. It may be "cute" now, but if it continues, it will eventually become annoying and the next "test" he gives her, may result in her deciding she's had enough and is ready to move on to a relationship with a more mature guy.