Some of the tests in cron_test.go seem to fail intermittently due to race conditions. The test schedules a job for 1 second and 2 seconds in the future (in absolute time), waits 2 seconds and checks it's been called twice, which sometimes doesn't occur reliably. For further details, see
https://bugzilla.redhat.com/show_bug.cgi?id=1714432#c7