Fear & Loathing in the MetaClassRegistry

On your testing travels you may, on occasion, mock methods out on certain classes using the old metaClass trick:
MyLovelyClass.metaClass.'static'.myLovelyMethod = { //crazy stuff here }
Now the fun with this approach is that when/how/where/how long/huh? feeling you get when you realize that other tests in the the suite start failing - dreaded test bleed (insert dramatic soundclip here).

Thanks to the Groovy method reference operation (&) and the MetaClassRegistry all can be made well, without having to resort to sticking all the initial method references in a map (or similar) and trying to stuff it all back on the original class in your tearDown():

void tearDown() {
def remove = GroovySystem.metaClassRegistry.&removeMetaClass
remove MyLovelyClass
}

Hmmm. I feel a bit lightheaded. Maybe you should drive.