added doc for writing tests
added doc for writing tests

cjaoude/Codeception,Pyrotoxin/Codeception,namnv609/Codeception,Codeception/base,TehJoE/Codeception,justintilson/Codeception,tiger-seo/Codeception,Naktibalda/Codeception,tasselchof/Codeception,sergeyklay/Codeception,namnv609/Codeception,Vitafy/Codeception,JarJak/Codeception,Codeception/Codeception,vml-rmott/Codeception,kt81/Codeception,SunDrop/Codeception,nett55/Codeception,may-den/Codeception,justintilson/Codeception,Vreasy/Codeception,hubbyist/Codeception,mkudenko/Codeception,JarJak/Codeception,pecinaon/Codeception,Codeception/Codeception,yhbyun/Codeception,pitpit/Codeception,arduanov/Codeception,sergeyklay/Codeception,pecinaon/Codeception,janthurau/Codeception,JakobReiter/Codeception,Naktibalda/Codeception,tiger-seo/Codeception,EspadaV8/Codeception,Vreasy/Codeception,orhan-swe/Codeception,yhbyun/Codeception,bizmate/Codeception,kt81/Codeception,janhenkgerritsen/Codeception,arduanov/Codeception,nett55/Codeception,janhenkgerritsen/Codeception,fbidu/Codeception,mkudenko/Codeception,tasselchof/Codeception,tasselchof/Codeception,SunDrop/Codeception,fbidu/Codeception,Vitafy/Codeception,Codeception/base,Pyrotoxin/Codeception,EspadaV8/Codeception,Naktibalda/Codeception,cjaoude/Codeception,may-den/Codeception,TehJoE/Codeception,pitpit/Codeception,Codeception/base,JakobReiter/Codeception,orhan-swe/Codeception,vml-rmott/Codeception,bizmate/Codeception,janthurau/Codeception,hubbyist/Codeception