pytest 4 and autopkgtest dependency loops

[Scott Talbert]

Hi,

Ondřej, I saw you uploaded pytest 4.  This has caused autopkgtest failures 
in a few of the packages I maintain, which I've been working on fixing.  I 
think those should be fine once they migrate to testing, as it should 
clear the autopkgtest failure from pytest 4.

However, there's one package that seems like it is going to cause a 
problem.  I uploaded pytest-xdist 1.29.0-1, which *requires* pytest 4, so 
pytest-xdist won't migrate to testing until pytest 4 does.  On the other 
hand, pytest 4 won't migrate to testing until all its autopkgtest failures 
(which include pytest-xdist) clear (right?).  So it seems we have a loop 
here.  How do we resolve it?

Scott