Add execution ctx tests.
Add execution ctx tests.

ghukill/peewee,d1hotpep/peewee,zhang625272514/peewee,wenxer/peewee,coreos/peewee,jarrahwu/peewee,jarrahwu/peewee,new-xiaji/peewee,softside/peewee,zhang625272514/peewee,coreos/peewee,jnovinger/peewee,Dipsomaniac/peewee,Sunzhifeng/peewee,new-xiaji/peewee,bopo/peewee,stas/peewee,coreos/peewee,fuzeman/peewee,ronyb29/peewee,Sunzhifeng/peewee,jarrahwu/peewee,Sunzhifeng/peewee,Dipsomaniac/peewee,d1hotpep/peewee,Dipsomaniac/peewee,teserak/peewee,zhang625272514/peewee,coleifer/peewee,fuzeman/peewee,mackjoner/peewee,lez/peewee,bopo/peewee,coleifer/peewee,py4a/peewee,coleifer/peewee,new-xiaji/peewee,jnovinger/peewee,wenxer/peewee,bopo/peewee