# Preparations
* in IDE:
# go to {nav Languages & Frameworks > PHP > Debug} section of PhpStorm settings dialog
# set `Max simultaneous connections` setting to `3`
# save changes
* in Admin Console:
# go to {nav Configuration > Website > Advanced} section
# enable `Use Cron to run Scheduled Tasks` setting
# save changes
# go to {nav Configuration > Website > Scheduled Tasks} section
# disable all scheduled tasks
# pick several tasks, that are executed each minute (update `Run Schedule` of any other task to make it usable in the test)
# enable picked tasks (Cancel them if they're marked as running currently)
* in IDE:
# replace body of above chosen scheduled tasks with `echo #' . getmypid() . ' - ' . $event . PHP_EOL;
# place breakpoint on `foreach ($events_source as $short_name => $event_data) {` line in `\kScheduledTaskManager::runAll` method
* in Terminal (start 2 windows in parallel):
# enable debugging from CLI
# run `php tools/cron.php` in folder of the project
# Test Plan
Goal is to test, that even if both `tools/cron.php` started with same available scheduled task list they won't execute scheduled tasks, that were processed from parallel process.