A formal testbench is a structured and constraint-aware environment designed to maximize the power of proof-based tools. It is built using modular components that reflect the key interactions of the system under verification while supporting exhaustive state-space exploration. Unlike simulation-based testbenches, formal environments are not driven by temporal sequences but by symbolic exploration of all valid input conditions and state transitions. The architecture incorporates several independent elements: behavioral models that define cycle-based behavior, symbolic constraints that narrow the legal stimulus space, and property checkers that define correctness expectations across multiple abstraction layers. Testbenches rely heavily on behavioral abstraction using cycle-accurate models. These models describe sequential timing relations between interface signals and are crucial for capturing design intent. By isolating temporal behavior into models, the testbench can remain portable and reusable. Input constraints play an equally important role by bounding input behavior to valid operating scenarios. These constraints ensure the proof engine focuses only on legal design conditions...