node --test prints spec, not TAP, into a pipe since Node 23, so filters for TAP lines match nothing

Fact

Up to Node 22, node --test used the tap reporter whenever stdout was not a terminal, so piped or redirected output had ok / not ok lines and a # pass N / # fail N summary. Since v23.0.0 the default is spec there too: ✔ / ✖ per test and a summary of ℹ pass N, ℹ fail N. Nothing warns about the change.

Why it matters

A script or CI step that greps the piped output for TAP lines (^not ok, ^# fail) matches nothing at all on every release since 23, LTS lines included, and an empty match is easily read as zero failures. The same npm test | grep ... answers differently on two machines whose only difference is the Node major.

How to apply

• Decide pass or fail by the exit code, which is non-zero on any failure with every reporter; never by the absence of a failure line.
• When a tool must parse the results, name the reporter instead of relying on the default: --test-reporter=tap, or --test-reporter=junit --test-reporter-destination=results.xml for CI dashboards.
• To skim a long run by eye on 23+, filter for ^ℹ (the summary) and ✖ (failures).