Basic PatchManager unit tests
Basic PatchManager unit tests

Tests to make sure it generates proper diff output.

Bug: T130805
Change-Id: Ic85d8f41583ad1c64ab1316e92528c6773db15cd

jayvdb/pywikibot-core,npdoty/pywikibot,magul/pywikibot-core,happy5214/pywikibot-core,hasteur/g13bot_tools_new,happy5214/pywikibot-core,npdoty/pywikibot,jayvdb/pywikibot-core,hasteur/g13bot_tools_new,Darkdadaah/pywikibot-core,magul/pywikibot-core,wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core,Darkdadaah/pywikibot-core,hasteur/g13bot_tools_new,wikimedia/pywikibot-core