fix: 修复聊天系统编译错误

- 修复 WebSocketManager/SocketIOClient 函数缩进错误
- 重命名 is_connected() 避免与 Object 基类冲突
- 修复 tscn 文件多余前导空格
- 修复测试文件 GUT 断言函数调用
- 添加 GUT 测试框架

addons/gut/one_to_many.gd

@@ -0,0 +1,43 @@
+# ------------------------------------------------------------------------------
+# This datastructure represents a simple one-to-many relationship.  It manages
+# a dictionary of value/array pairs.  It ignores duplicates of both the "one"
+# and the "many".
+# ------------------------------------------------------------------------------
+var items = {}
+
+# return the size of items or the size of an element in items if "one" was
+# specified.
+func size(one=null):
+	var to_return = 0
+	if(one == null):
+		to_return = items.size()
+	elif(items.has(one)):
+		to_return = items[one].size()
+	return to_return
+
+
+# Add an element to "one" if it does not already exist
+func add(one, many_item):
+	if(items.has(one)):
+		if(!items[one].has(many_item)):
+			items[one].append(many_item)
+	else:
+		items[one] = [many_item]
+
+
+func clear():
+	items.clear()
+
+
+func has(one, many_item):
+	var to_return = false
+	if(items.has(one)):
+		to_return = items[one].has(many_item)
+	return to_return
+
+
+func to_s():
+	var to_return = ''
+	for key in items:
+		to_return += str(key, ":  ", items[key], "\n")
+	return to_return