Key takeaway
A good test system defines what was checked, how it was checked and what the result means.
Start with the decision the test must support
A test fixture should not exist only because testing is desirable. It should answer a practical question: is this module safe to install, is this function present, or is this assembly behaving consistently enough to proceed?
Define test limits clearly
Some functions can be bench verified and others require the original machine. Clear limits protect the customer from overconfidence and help technicians interpret results correctly.
Design for repeat use
Labelling, connectors, software steps, pass/fail thresholds and safety notes make the test useful beyond the person who built it.
Use test evidence in handover
Test results become part of the support record. They help future teams compare behaviour, investigate changes and make faster decisions.