Got this one from "Get Anyone To Do Anything" by David Lieberman. This 6 part test will basically give you a pretty good idea as to who your real friends are and who the fakers are. If they pass at least 4 out of 6, good. 3 or less, well.
The Respect Test
You tell the person there is something exciting going on in your life but you can't tell just yet. If they are a true friend they will respect you by not prying after you said you would tell them later. The faker will insist that you tell them and they will pry and pry until you can't stand it. POINT: don't tell them that something bad has happened, because they will definately worry about you.
The Loyalty Test
Tell a secret about a friend that you both have and see if it gets back to them. The friend will stay loyal by keeping the secret to herself. The faker will tell others and eventually it'll get back to the mutual friend. POINT: make sure you get the mutual friends permission to tell them the secret first.
The Interest Test
A good friend will always be interested in what's going on in your life. To see if he is a good friend in this regard, tell him something that is presently taking place in your like. The friend will follow up with this event and ask you how its progressing. The faker won't ask you anything about it, they probably forgot about it as soon as you told them. Also ask to see if they remember it after a while.
The Pride Test
Tell your friend about something you recently accomplished. The friend will be proud of your success. The faker will be jealous and they probably won't congratulate you at all.
The Sacrifice Test
When your back is against the wall and you need help, see if she helps you out. A friend will develop a plan to take care of both of yall. The faker will say "to hell with you" and only look out for their own interests.
The Honesty Test
A true friend will tell it like it is regardless of whether it hurts your feelings or not. A faker will only tell you what you want to hear.
Try it out.