Yes there has been a vacuum test
heres the results from eagleworks using a Nasa lab.
Faster-than-light travel may be a possibility after an accidental discovery by NASA scientists, but researchers are cautioning observers not to get too excited about taking a week-long trip to Alpha Centauri just yet. The new engine technology — once believed to be impossible — is now successful in tests for the third time.
The electromagnetic (EM) propulsion drive, or EM Drive, which might make hyperspace travel possible bounces microwaves within a closed container in order to provide thrust. This very notion appears to be contrary to some of the most basic laws of physics, including Newton's Third Law of Motion, which states that for every action, there is an equal but opposite reaction. Traditional rocket engines are driven by this tenet of physics — as propellant is accelerated out through the exhaust of an engine, the movement creates an opposite reaction pushing the spaceship forward.
https://www.google.ie/search?client=ubuntu&channel=fs&q=warp+drive&ie=utf-8&oe=utf-8&gws_rd=cr&ei=wOVIVa-DM6ip7AaWsYB4#q=warp+drive&channel=fs&tbm=nws