TST: add test coverage for maybe_promote#23982

Merged

jreback merged 11 commits intopandas-dev:masterfrom

h-vetinari:tst_maybe_promote

Oct 11, 2019

Commits on Feb 24, 2019

Commits on Sep 21, 2019

blackify conflict files before merge
h-vetinari
committed

Commits on Sep 22, 2019

Merge remote-tracking branch 'upstream/master' into tst_maybe_promote
h-vetinari
committed

Commits on Oct 11, 2019