The draft paper defines a system, which is capable of maintaining bases of test cases for logical specifications. The specifications, which are subject to this system are transformed from their original shape in first-order logic to form-based expressions as originally introduced in logics of George Spencer-Brown. The innovation comes from the operations the system provides when injecting faults - so-called mutations - to the specifications. The system presented here applies to logical specifications from areas as different as programming, ontologies or hardware specifications.