I read that the first test was a failure but another theory says that could be done but it may violate the laws of physics. Is this engine a near future possible propulsion system or is just theory per se?
It appears to be unworkable.
If Burns had properly accounted for the total momentum of the box+ring system, which must include the energy/momentum of the applied fields and forces required to accelerate the individual components (like the ring) inside the box, he would have noted that the total momentum never changes, even under relativistic transformations and perfectly elastic ring/box collisions.
Even the designer himself says
Basic concept is unproven
Has not been reviewed by subject-matter experts
Math errors may exist!
Both sources say that the energy/momentum of the forces and fields used to accelerate the particles have been neglected. Once this is considered, conservation of momentum still applies.