I have no problems with a submissive testing her leash, finding out what is acceptable and what isn't. I don't want a sub that feels like she can't tease me and be a bit unruly at times as long as she understands that I will draw the line and bring her back under control when and how I wish. Just like with a puppy, you may play tug of war with them or let them get a little rough but as soon as the command is given, they should stop and obey.

Testing in the form mentioned by DowntownAmber would be totally unacceptable.