Fix a subtle test collection problem in testing
Fix a subtle test collection problem in testing

aleksandr-bakanov/astropy,saimn/astropy,saimn/astropy,saimn/astropy,mhvk/astropy,lpsinger/astropy,StuartLittlefair/astropy,pllim/astropy,stargaser/astropy,StuartLittlefair/astropy,mhvk/astropy,lpsinger/astropy,stargaser/astropy,mhvk/astropy,saimn/astropy,aleksandr-bakanov/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,mhvk/astropy,lpsinger/astropy,MSeifert04/astropy,MSeifert04/astropy,dhomeier/astropy,dhomeier/astropy,larrybradley/astropy,astropy/astropy,dhomeier/astropy,mhvk/astropy,astropy/astropy,dhomeier/astropy,astropy/astropy,StuartLittlefair/astropy,pllim/astropy,lpsinger/astropy,MSeifert04/astropy,bsipocz/astropy,lpsinger/astropy,MSeifert04/astropy,larrybradley/astropy,pllim/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,larrybradley/astropy,stargaser/astropy,dhomeier/astropy,larrybradley/astropy,StuartLittlefair/astropy,bsipocz/astropy,astropy/astropy,pllim/astropy,bsipocz/astropy,stargaser/astropy,bsipocz/astropy,astropy/astropy,pllim/astropy,saimn/astropy