Writing covergroups is the easy half. Closure is the loop that turns coverage numbers into a defensible claim that verification is done: plan from the spec, merge regressions, triage each hole, act on its class, and assemble the sign-off evidence.
Lesson | What it covers |
|---|---|
Spec values, combinations, sequences, and boundaries turned into a plan table with IDs and priorities. | |
Merged reports, four hole classes, the cheapest-first flow, and five worked holes. | |
Constraint steering, directed tests, seed sweeps, bin fixes, and the diminishing-returns curve. | |
Legitimate criteria, waiver records, file hygiene, and the bulk-exclusion trap. | |
Four instruments, per-feature numbers, and the final review checklist. |
Whether the bin itself is correct: range, signal, and sample event. A wrong bin invalidates its history, and checking it costs minutes while a directed test costs days.