You can tell if there's meth in it by:
-Onset: meth takes an hour at least to kick in, MDMA takes around 45 minutes.
-Loveyness/euphoria: Meth just gives you lots of energy with no feeling of connectedness, MDMA gives a distinct loving feeling, they don't call it ecstasy for nothing.
-Duration: Meth lasts double the time MDMA does, and does a very good job of keeping you awake, if you fell asleep without much problem it's very unlikely that there was meth in it.
I believe that if heroin users get safe injection sites, ecstasy users should get laboratory pill testing. Holland has the right idea, you can take your pill to a lab and get it tested. Ecstasy is still not legal there but they have a system based on the ideology of: People are going to do it anyway, might as well make it safe.