Nik Everett d536854879 Fix test bug in auto_date_histo
The test would try to prepare a `Rounding` even when there aren't any
buckets. This would fail because there is no range over which to prepare
the rounding. It turns out that we don't need the rounding in that case
so we just use `null` then.

Closes #59131
2020-07-07 15:39:48 -04:00
..
2020-07-07 15:39:48 -04:00