Add test of full precision roundtrip
Add test of full precision roundtrip

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