We’ve looked at why teams should consider doing TDD; we’ve looked at how the roles and responsibilities change between design and verification experts; now let’s look at when everything happens. This is the key to seeing how everything fits together.
Most teams nowadays chose to split their verification effort up as a combination of block level and top level testing. Block level testing is usually applied to every subsystem in a design and intended to exhaustively cover all the features of each subsystem. Once the block level testing is done, the exhaustively tested pieces are integrated and tested in a top level testbench.
