shorebird-updater/shorebird_code_push/test/override_print.dart

import 'dart:async';

void Function() overridePrint(void Function(List<String> logs) fn) {
  return () {
    final printLogs = <String>[];
    final spec = ZoneSpecification(
      print: (_, __, ___, String msg) {
        printLogs.add(msg);
      },
    );

    return Zone.current
        .fork(specification: spec)
        .run<void>(() => fn(printLogs));
  };
}