added self referential test
added self referential test

Cito/sqlalchemy,alex/sqlalchemy,hsum/sqlalchemy,davidfraser/sqlalchemy,EvaSDK/sqlalchemy,inspirehep/sqlalchemy,276361270/sqlalchemy,monetate/sqlalchemy,hsum/sqlalchemy,j5int/sqlalchemy,276361270/sqlalchemy,epa/sqlalchemy,wujuguang/sqlalchemy,olemis/sqlalchemy,halfcrazy/sqlalchemy,bdupharm/sqlalchemy,Akrog/sqlalchemy,sandan/sqlalchemy,dstufft/sqlalchemy,Akrog/sqlalchemy,Cito/sqlalchemy,sandan/sqlalchemy,halfcrazy/sqlalchemy,graingert/sqlalchemy,Cito/sqlalchemy,sqlalchemy/sqlalchemy,robin900/sqlalchemy,wfxiang08/sqlalchemy,elelianghh/sqlalchemy,itkovian/sqlalchemy,olemis/sqlalchemy,WinterNis/sqlalchemy,j5int/sqlalchemy,davidfraser/sqlalchemy,itkovian/sqlalchemy,pdufour/sqlalchemy,EvaSDK/sqlalchemy,davidjb/sqlalchemy,alex/sqlalchemy,wujuguang/sqlalchemy,robin900/sqlalchemy,brianv0/sqlalchemy,davidjb/sqlalchemy,wfxiang08/sqlalchemy,brianv0/sqlalchemy,pdufour/sqlalchemy,inspirehep/sqlalchemy,WinterNis/sqlalchemy,bootandy/sqlalchemy,bootandy/sqlalchemy,zzzeek/sqlalchemy,ThiefMaster/sqlalchemy,alex/sqlalchemy,graingert/sqlalchemy,monetate/sqlalchemy,epa/sqlalchemy,elelianghh/sqlalchemy,dstufft/sqlalchemy,ThiefMaster/sqlalchemy,bdupharm/sqlalchemy