diff --git a/src/emqttd_mqueue.erl b/src/emqttd_mqueue.erl
index 956a6dad5..d9f3c3c58 100644
--- a/src/emqttd_mqueue.erl
+++ b/src/emqttd_mqueue.erl
@@ -53,6 +53,7 @@
 -author("Feng Lee <feng@emqtt.io>").
 
 -include("emqttd.hrl").
+
 -include("emqttd_protocol.hrl").
 
 -export([new/3, name/1,
@@ -112,10 +113,9 @@ len(#mqueue{len = Len}) -> Len.
 %% @end
 %%------------------------------------------------------------------------------
 
--spec in({newcome | pending, mqtt_message()}, mqueue()) -> mqueue().
-
+-spec in(mqtt_message(), mqueue()) -> mqueue().
 %% drop qos0
-in({_, #mqtt_message{qos = ?QOS_0}}, MQ = #mqueue{qos0 = false}) ->
+in(#mqtt_message{qos = ?QOS_0}, MQ = #mqueue{qos0 = false}) ->
     MQ;
 
 %% simply drop the oldest one if queue is full, improve later
diff --git a/test/emqttd_mqueue_tests.erl b/test/emqttd_mqueue_tests.erl
new file mode 100644
index 000000000..8e6c4fb16
--- /dev/null
+++ b/test/emqttd_mqueue_tests.erl
@@ -0,0 +1,71 @@
+%%%-----------------------------------------------------------------------------
+%%% @Copyright (C) 2012-2015, Feng Lee <feng@emqtt.io>
+%%%
+%%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%%% of this software and associated documentation files (the "Software"), to deal
+%%% in the Software without restriction, including without limitation the rights
+%%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%%% copies of the Software, and to permit persons to whom the Software is
+%%% furnished to do so, subject to the following conditions:
+%%%
+%%% The above copyright notice and this permission notice shall be included in all
+%%% copies or substantial portions of the Software.
+%%%
+%%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+%%% SOFTWARE.
+%%%-----------------------------------------------------------------------------
+
+-module(emqttd_mqueue_tests).
+
+-include("emqttd.hrl").
+
+-define(QM, emqttd_mqueue).
+
+-ifdef(TEST).
+
+-include_lib("eunit/include/eunit.hrl").
+
+in_test() ->
+    Opts = [{max_length, 5},
+            {queue_qos0, true}],
+    Q = ?QM:new(<<"testQ">>, Opts, alarm_fun()),
+    ?assertEqual(true, ?QM:is_empty(Q)),
+    Q1 = ?QM:in(#mqtt_message{}, Q),
+    ?assertEqual(1, ?QM:len(Q1)),
+    Q2 = ?QM:in(#mqtt_message{qos = 1}, Q1),
+    ?assertEqual(2, ?QM:len(Q2)),
+    Q3 = ?QM:in(#mqtt_message{qos = 2}, Q2),
+    Q4 = ?QM:in(#mqtt_message{}, Q3),
+    Q5 = ?QM:in(#mqtt_message{}, Q4),
+    ?assertEqual(true, ?QM:is_full(Q5)).
+    
+in_qos0_test() ->
+    Opts = [{max_length, 5},
+            {queue_qos0, false}],
+    Q = ?QM:new(<<"testQ">>, Opts, alarm_fun()),
+    Q1 = ?QM:in(#mqtt_message{}, Q),
+    ?assertEqual(true, ?QM:is_empty(Q1)),
+    Q2 = ?QM:in(#mqtt_message{qos = 0}, Q1),
+    ?assertEqual(true, ?QM:is_empty(Q2)).
+
+out_test() ->
+    Opts = [{max_length, 5},
+            {queue_qos0, true}],
+    Q = ?QM:new(<<"testQ">>, Opts, alarm_fun()),
+    ?assertMatch({empty, Q}, ?QM:out(Q)),
+    Q1 = ?QM:in(#mqtt_message{}, Q),
+    {Value, Q2} = ?QM:out(Q1),
+    ?assertEqual(0, ?QM:len(Q2)),
+    ?assertMatch({value, #mqtt_message{}}, Value).
+ 
+alarm_fun() ->
+   fun(_, _) -> alarm_fun() end.
+
+-endif.
+
+