UFO over 5 Points, Union , NJ

We were 4 professional young adults, ages 22-25 ou on a quick grocery run to the A & P in a very busy location known as Five Points.   We parked in the lot facing the store.  One of us ran in to get the item, the rest remained in the vehicle/VW Camper.
We were sitting quietly waiting when suddenly the person in the front, passenger seat exclaimed, "Holy s--- , I see something coming up in the side view mirror and it ain't no plane!!" 
We all said, "Huh, what?"   Then, by that time we saw it, it was over then behind the store several hundred feet up.
We can best describe it as a perfect, seamless, metalic saucer with sequential white lights, almost like strobe lights flashing.  The object was quiet, and hovered for quit a while. One of us ran into the store to get the 4th person. We checked people in the lot and saw many looking up too.
At one point the craft/UFO 's lights went off, another time ir flew up , high fast, then came down low. We actually thought it may land, but it always remained above the store roof, actually behind, but up,  We watched it oo up and down, figured they were testing the craft by now....finally it just took off, went north east toward the Garden State Parkway, very low, then took off like you see in Star Trek.  We were able to view it in the night sky though because of it lights.  We could see it move east toward Newark Airport then in 3 sec west, it was like a star moving across the sky, making all sorts of sudden stops, right hand turns at 90 degree angles.  Definitely seemed as if they were checking it out. We left the parkway when we no longer saw it.
Witness elects to remain totally anonymous; provides no contact information.  PD