fix: harden quest poi filtering and objective refresh

Tests/QuestEventHandlerObjectiveRefresh_spec.lua

@@ -0,0 +1,28 @@
+local function read(path)
+    local f = assert(io.open(path, "r"), "cannot open " .. path)
+    local content = f:read("*a")
+    f:close()
+    return content
+end
+
+local function has(content, needle)
+    return content:find(needle, 1, true) ~= nil
+end
+
+describe("Quest objective refresh events", function()
+    local handler = read("Modules/Quest/QuestEventHandler.lua")
+
+    it("does not depend on a later QUEST_LOG_UPDATE after QUEST_WATCH_UPDATE", function()
+        local start = assert(handler:find("function _QuestEventHandler:QuestWatchUpdate", 1, true))
+        local finish = assert(handler:find("local _UnitQuestLogChangedCallback", start, true))
+        local body = handler:sub(start, finish)
+
+        assert.is_true(has(handler, "_questWatchUpdateDebounceTimer"))
+        assert.is_true(has(handler, "_questWatchUpdateFollowUpTimer"))
+        assert.is_true(has(body, "QuestieQuest:SetObjectivesDirty(questId)"))
+        assert.is_true(has(body, "state = QUEST_LOG_STATES.QUEST_ACCEPTED"))
+        assert.is_true(has(body, "C_Timer.NewTimer(0.2"))
+        assert.is_true(has(body, "C_Timer.NewTimer(1.0"))
+        assert.is_true(has(body, "_QuestEventHandler:QuestLogUpdate()"))
+    end)
+end)