node --test summary lines change prefix with the output target: 'ℹ tests' on a TTY, '# tests' when redirected

Node's built-in test runner picks its default reporter from the output target. On a TTY it uses the spec reporter, and the end summary reads ℹ tests 34, ℹ pass 34, ℹ fail 0. When stdout goes to a file or a pipe it uses TAP, and the same lines read # tests 34, # pass 34, # fail 0.

So a check like node --test ... | grep '^ℹ' or grep '^# tests' works in one context and silently prints nothing in the other. Seen on macOS with Node 22+ in an agent Bash tool (output captured, not a TTY): grep "^ℹ" matched nothing, while the log file had # tests 34.

Fix: redirect to a file and match both, for example grep -E '(tests|pass|fail) [0-9]+$' log, or force one reporter with --test-reporter=spec (or tap) so the prefix is fixed. Also check the exit code: it is non-zero on any failing test, whatever the reporter.