Preparations

• in IDE:
  1. go to Languages & Frameworks → PHP → Debug section of the PhpStorm settings dialog
  2. set Max simultaneous connections setting to 3
  3. save changes
• in Admin Console:
  1. go to Configuration → Website → Advanced section
  2. enable Use Cron to run Scheduled Tasks setting
  3. save changes
  4. go to Configuration → Website → Scheduled Tasks section
  5. disable all scheduled tasks
  6. pick several tasks that are executed each minute (update Run Schedule of any other task to make it usable in the test)
  7. enable picked tasks (Cancel them if they're marked as running currently)
• in IDE:
  1. replace the body of the above-chosen scheduled tasks with echo #' . getmypid() . ' - ' . $event . PHP_EOL;
  2. place breakpoint on if ( !$this->claim($event_data, $start_time) ) { line in \kScheduledTaskManager::runAll method
• in Terminal (start 2 windows in parallel):
  1. enable debugging from CLI
  2. run php tools/cron.php in the folder of the project

Test Plan

1. in the 1st process use Step Over in PhpStorm
2. confirm that claiming succeeded and you're able to execute the $this->run($event_data, $start_time); line
3. in the 2nd process use Step Over in PhpStorm
4. confirm that claiming failed and you're redirect to the next scheduled task execution (if any)