Add tests for OrderedSet type.
Add tests for OrderedSet type.

StackStorm/st2,StackStorm/st2,Plexxi/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2,nzlosh/st2,nzlosh/st2,Plexxi/st2