Weak Auras magic

I'd like to ask if somebody has experience with making custom WeakAuras that are tied to hard-to-replicate events in game. I am trying to make WA that announces who steps out cloud at Yogg-Saron, but replicating, not to say testing these things out require either sandbox realm or inhumanely patient group. How do you rapidly test and make theese things?

Secondly...specifically
As I said I'm making WA fo Yogg-Saron clouds.:

CHAT_MSG_RAID_BOSS_EMOTE

trigger code:

function(m, n, ...)
local pattern = "Ominous Cloud begins to boil upon touching "
if string.find(m, pattern) then
name = string.sub(m, string.len(pattern))
SendChatMessage(name .. "triggered cloud.", "SAY", DEFAULT_CHAT_FRAME.editBox.languageID);
SendChatMessage(n , "SAY", DEFAULT_CHAT_FRAME.editBox.languageID);
return true
end
return false
end

I am wondering wether somebody more experienced with LUA and WoW API can help me, and spare me x pulls of Y-S to make it right.