Review Effective Configuration Precedence in PCB Test Software

A configuration file can contain the intended value while the running test uses something else. Defaults, inherited sections, environment settings, command-line options, and operator overrides may all participate in resolution. Review the effective configuration rather than approving one file in isolation.

Python’s ConfigParser documentation gives a concrete example: values in the default section take precedence over a fallback supplied to a lookup. Other configuration systems have their own rules, so confirm the behavior of the implementation actually deployed.

Write down the resolution order

List every configuration source and the order in which it is applied. Identify which settings are allowed to vary by station, product, fixture, or operator session. A station-specific communication address may be appropriate, while an operator-specific acceptance limit may not be.

For consequential settings, retain the final value and its source. This turns an unexpected behavior into a traceable resolution question rather than a search through several files that each appear plausible.

Distinguish required values from conveniences

A fallback that is harmless for a report color can be inappropriate for a test condition. Avoid applying one generic “use default” policy to every missing key. Define the policy according to the effect on the measurement and production decision.

Exercise conflicting inputs

Create a validation case in which two sources deliberately specify different values. Confirm which one wins and how the resolved value is recorded. Repeat with a missing key, an empty value, a misspelled section, and a value of the wrong type.

Perform this check at the point where the test consumes the setting. A startup log can be correct while a later module reloads a file or applies another override. Freeze the complete configuration for the attempt where consistency is required, or explicitly record any approved change during execution.

Keep development overrides out of the released configuration package unless their production use is defined. A temporary option can otherwise remain active long after its original troubleshooting purpose has been forgotten.

Archive enough information to reconstruct the effective configuration for a historical attempt. The useful release evidence is not simply “the settings file was present”; it shows which values governed the run, where they came from, and why the software accepted that combination.