The paper presents an embedded self test circuit for adaptive systems whose exact specification is unknown. In particular, a functional testing mechanism for systems that have an acceptable representation as polynomials of low order is introduced. The testing mechanism is based on linear-checks and is suitable for Walsh transform based architectures. The paper shows that it is possible to define a small set of linear-checks which does not depend on the actual functionality that the hardware has converged to. Moreover, the check-set can be defined even without knowing the number of input variables nor their precision. In addition, the implementation cost of this testing scheme is negligible in respect to the cost of overall system.