Make sure exceptions thrown on hook_cron() don't affect other modules.
function testCronExceptions() {
\Drupal::state()
->delete('common_test.cron');
// The common_test module throws an exception. If it isn't caught, the tests
// won't finish successfully.
// The common_test_cron_helper module sets the 'common_test_cron' variable.
$this
->cronRun();
$result = \Drupal::state()
->get('common_test.cron');
$this
->assertEqual($result, 'success', 'Cron correctly handles exceptions thrown during hook_cron() invocations.');
}