Circuits that allow short unit diagnostic tests

We study the possibility of constructing easily testable circuits of functional elements in the basis $\{\&,\vee,^-\}$ with single-type constant faults at the inputs and the outputs of the elements. We constructively establish that any Boolean function of $n$ variables can be realized by a circuit that allows a unit diagnostic test whose length with respect to order does not exceed $\sqrt{2^n}$.