Add test for interval of a few months
Add test for interval of a few months

lpsinger/astropy,larrybradley/astropy,lpsinger/astropy,larrybradley/astropy,StuartLittlefair/astropy,mhvk/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,pllim/astropy,mhvk/astropy,mhvk/astropy,aleksandr-bakanov/astropy,saimn/astropy,pllim/astropy,lpsinger/astropy,pllim/astropy,astropy/astropy,mhvk/astropy,lpsinger/astropy,astropy/astropy,astropy/astropy,astropy/astropy,saimn/astropy,StuartLittlefair/astropy,pllim/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,saimn/astropy,astropy/astropy,saimn/astropy,saimn/astropy,larrybradley/astropy,larrybradley/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,pllim/astropy,larrybradley/astropy,StuartLittlefair/astropy,mhvk/astropy