Sam Minnee 2c71daacfe MINOR: Add tests for GroupedDropdownField empty strings
These bugs were never present in SS4 as the relevant code had a
substantial rewrite at the same time they were introduced in SS3.
In SS3, test C still fails.

Fixes #4705
Fixes #4987
Fixes #4793
2019-05-27 17:46:03 +12:00
..
2019-03-20 13:19:10 +13:00