Choose a verification method for each failure mode. Optical inspection, X-ray, bare-board continuity testing and functional testing provide different evidence. The useful question is what the implemented method can detect on this particular board.
Start with these questions
- Which failures must be detected before shipment?
- Can the required nodes and hidden joints be accessed?
- Are limits, firmware and test-program revisions controlled?
Read the engineering guides
Apply a tool or checklist
What to keep in the project record
Release a test sequence with defined inputs, loads, limits, traceability and retest handling. Keep product qualification separate from manufacturing workmanship acceptance.