Unit Benches + Integration Bench Mental Model

Test each component in isolation, then exercise the stitched design with an integration testbench.
Design & Testbenches
Design / component blocks
Unit testbenches → component
Integration bench → stitched design
Test plan
Unit benches: waiting | Integration: waiting
Sequence
Why both?
Unit benches make it easy to poke and assert every port of a single module without other logic in the way. The integration bench uses realistic traffic and timing to catch interface and wiring issues between modules.