Add a test for a failing unification case
Add a test for a failing unification case

cowlicks/datashape,llllllllll/datashape,quantopian/datashape,markflorisson/datashape,blaze/datashape,cpcloud/datashape,llllllllll/datashape,quantopian/datashape,ContinuumIO/datashape,FrancescAlted/datashape,ContinuumIO/datashape,FrancescAlted/datashape,blaze/datashape,markflorisson/datashape,aterrel/datashape,cowlicks/datashape,aterrel/datashape,cpcloud/datashape