Adding line of text to player tooltip

[MinguasBeef]

I've been having trouble getting this to work...

I want it so that when I mouse over a player, or unit that there will be an extra line of text in the tooltip window.

I tried hooking SetUnit, but didn't have any luck.

function AdditionalUnitText(unit)
	GameTooltip:AddLine("Test", 1, 1, 1)
	GameTooltip:Show()
end
hooksecurefunc(GameTooltip,"SetUnit",AdditionalUnitText)