That photo of aircraft in the test set-up: I can't identify it. It doesn't look like a mock-up or wind tunnel model. The aircraft looks almost like it is intended to fly, except for the lack of landing gear.
As other people have said, the engine intakes are not stealthy.
And how do the exhausts exhaust? Maybe there are hot nozzles we can't see.
Looks to me like the cool air is ducted upward into and through the wings to achieve jet flap effects.