The concept of applying fencing logic to Built-In Self Test (BIST)
hardware structures for the purpose of segregating defective circuitry
and utilizing the remaining good circuitry is a well known practice in
the chip design industry. Described herein is a method for verifying that
any particular implementation of partial fencing logic actually provides
the desired behavior of blocking down-stream impact of all signals from
fenced interfaces, and also ensuring that the partial fencing does not
inadvertently preclude any common logic from being fully tested.