ENH: Updated tests for series GroupBy whitelist
ENH: Updated tests for series GroupBy whitelist

Added tests for fix to pydata/pandas#6146.

dsm054/pandas,cython-testbed/pandas,TomAugspurger/pandas,linebp/pandas,GuessWhoSamFoo/pandas,amolkahat/pandas,nmartensen/pandas,DGrady/pandas,louispotok/pandas,jmmease/pandas,louispotok/pandas,DGrady/pandas,amolkahat/pandas,DGrady/pandas,amolkahat/pandas,gfyoung/pandas,gfyoung/pandas,gfyoung/pandas,gfyoung/pandas,jmmease/pandas,winklerand/pandas,rs2/pandas,nmartensen/pandas,linebp/pandas,harisbal/pandas,jorisvandenbossche/pandas,zfrenchee/pandas,amolkahat/pandas,dsm054/pandas,cbertinato/pandas,pratapvardhan/pandas,gfyoung/pandas,pratapvardhan/pandas,pandas-dev/pandas,Winand/pandas,rs2/pandas,amolkahat/pandas,kdebrab/pandas,jmmease/pandas,TomAugspurger/pandas,datapythonista/pandas,pratapvardhan/pandas,Winand/pandas,zfrenchee/pandas,Winand/pandas,linebp/pandas,toobaz/pandas,winklerand/pandas,GuessWhoSamFoo/pandas,winklerand/pandas,TomAugspurger/pandas,winklerand/pandas,kdebrab/pandas,cbertinato/pandas,toobaz/pandas,datapythonista/pandas,cbertinato/pandas,GuessWhoSamFoo/pandas,linebp/pandas,linebp/pandas,jmmease/pandas,TomAugspurger/pandas,pandas-dev/pandas,nmartensen/pandas,toobaz/pandas,DGrady/pandas,dsm054/pandas,harisbal/pandas,MJuddBooth/pandas,DGrady/pandas,dsm054/pandas,kdebrab/pandas,jreback/pandas,louispotok/pandas,rs2/pandas,Winand/pandas,zfrenchee/pandas,jmmease/pandas,harisbal/pandas,GuessWhoSamFoo/pandas,GuessWhoSamFoo/pandas,MJuddBooth/pandas,MJuddBooth/pandas,jmmease/pandas,datapythonista/pandas,cbertinato/pandas,zfrenchee/pandas,cython-testbed/pandas,jorisvandenbossche/pandas,louispotok/pandas,jorisvandenbossche/pandas,linebp/pandas,pandas-dev/pandas,nmartensen/pandas,jreback/pandas,winklerand/pandas,harisbal/pandas,jreback/pandas,cython-testbed/pandas,pratapvardhan/pandas,zfrenchee/pandas,cbertinato/pandas,nmartensen/pandas,pandas-dev/pandas,cython-testbed/pandas,jreback/pandas,rs2/pandas,nmartensen/pandas,harisbal/pandas,toobaz/pandas,kdebrab/pandas,datapythonista/pandas,dsm054/pandas,louispotok/pandas,kdebrab/pandas,Winand/pandas,DGrady/pandas,winklerand/pandas,jreback/pandas,jorisvandenbossche/pandas,MJuddBooth/pandas,pratapvardhan/pandas,MJuddBooth/pandas,toobaz/pandas,cython-testbed/pandas,Winand/pandas