diff --git a/test/emqx_channel_SUITE.erl b/test/emqx_channel_SUITE.erl
index 2c8bece49..9a3cd6ff3 100644
--- a/test/emqx_channel_SUITE.erl
+++ b/test/emqx_channel_SUITE.erl
@@ -95,7 +95,7 @@ t_chan_attrs(_) ->
     #{conn_state := connected} = emqx_channel:attrs(channel()).
 
 t_chan_caps(_) ->
-    Caps = emqx_channel:caps(channel()).
+    _Caps = emqx_channel:caps(channel()).
 
 %%--------------------------------------------------------------------
 %% Test cases for channel init
@@ -103,7 +103,7 @@ t_chan_caps(_) ->
 
 %% TODO:
 t_chan_init(_) ->
-    Channel = channel().
+    _Channel = channel().
 
 %%--------------------------------------------------------------------
 %% Test cases for channel handle_in
@@ -154,7 +154,7 @@ t_handle_in_qos2_publish(_) ->
 t_handle_in_puback_ok(_) ->
     Msg = emqx_message:make(<<"t">>, <<"payload">>),
     ok = meck:expect(emqx_session, puback,
-                     fun(PacketId, Session) -> {ok, Msg, Session} end),
+                     fun(_PacketId, Session) -> {ok, Msg, Session} end),
     Channel = channel(#{conn_state => connected}),
     {ok, _NChannel} = emqx_channel:handle_in(?PUBACK_PACKET(1, ?RC_SUCCESS), Channel).
     % ?assertEqual(#{puback_in => 1}, emqx_channel:info(pub_stats, NChannel)).
@@ -186,7 +186,7 @@ t_handle_in_pubrec_ok(_) ->
 
 t_handle_in_pubrec_id_in_use(_) ->
     ok = meck:expect(emqx_session, pubrec,
-                     fun(_, Session) ->
+                     fun(_, _Session) ->
                              {error, ?RC_PACKET_IDENTIFIER_IN_USE}
                      end),
     {ok, ?PUBREL_PACKET(1, ?RC_PACKET_IDENTIFIER_IN_USE), _Channel}
@@ -196,7 +196,7 @@ t_handle_in_pubrec_id_in_use(_) ->
 
 t_handle_in_pubrec_id_not_found(_) ->
     ok = meck:expect(emqx_session, pubrec,
-                     fun(_, Session) ->
+                     fun(_, _Session) ->
                              {error, ?RC_PACKET_IDENTIFIER_NOT_FOUND}
                      end),
     {ok, ?PUBREL_PACKET(1, ?RC_PACKET_IDENTIFIER_NOT_FOUND), _Channel}
@@ -360,7 +360,7 @@ t_handle_out_publish_nl(_) ->
     {ok, Channel} = emqx_channel:handle_out(Publish, Channel).
 
 t_handle_out_connack_sucess(_) ->
-    {ok, [{connack, ?CONNACK_PACKET(?RC_SUCCESS, SP, _)}], _Chan}
+    {ok, [{connack, ?CONNACK_PACKET(?RC_SUCCESS, _SP, _)}], _Chan}
         = emqx_channel:handle_out(connack, {?RC_SUCCESS, 0, connpkt()}, channel()).
 
 t_handle_out_connack_failure(_) ->
@@ -459,13 +459,13 @@ t_handle_timeout_emit_stats(_) ->
 
 t_handle_timeout_keepalive(_) ->
     TRef = make_ref(),
-    Channel = emqx_channel:set_field(timers, #{alive_timer => TRef}, channel()),
+    _Channel = emqx_channel:set_field(timers, #{alive_timer => TRef}, channel()),
     {ok, _Chan} = emqx_channel:handle_timeout(make_ref(), {keepalive, 10}, channel()).
 
 t_handle_timeout_retry_delivery(_) ->
     ok = meck:expect(emqx_session, retry, fun(Session) -> {ok, Session} end),
     TRef = make_ref(),
-    Channel = emqx_channel:set_field(timers, #{retry_timer => TRef}, channel()),
+    _Channel = emqx_channel:set_field(timers, #{retry_timer => TRef}, channel()),
     {ok, _Chan} = emqx_channel:handle_timeout(TRef, retry_delivery, channel()).
 
 t_handle_timeout_expire_awaiting_rel(_) ->
diff --git a/test/emqx_client_SUITE.erl b/test/emqx_client_SUITE.erl
index 8c3d55cec..adbb4fb94 100644
--- a/test/emqx_client_SUITE.erl
+++ b/test/emqx_client_SUITE.erl
@@ -251,7 +251,7 @@ t_basic_with_props_v5(_) ->
 %% General test cases.
 %%--------------------------------------------------------------------
 
-t_basic(Opts) ->
+t_basic(_Opts) ->
     Topic = nth(1, ?TOPICS),
     {ok, C} = emqtt:start_link([{proto_ver, v4}]),
     {ok, _} = emqtt:connect(C),
diff --git a/test/emqx_session_SUITE.erl b/test/emqx_session_SUITE.erl
index 621fe4aa5..224c3ff60 100644
--- a/test/emqx_session_SUITE.erl
+++ b/test/emqx_session_SUITE.erl
@@ -128,12 +128,12 @@ t_publish_qos2(_) ->
 t_publish_qos1(_) ->
     ok = meck:expect(emqx_broker, publish, fun(_) -> [] end),
     Msg = emqx_message:make(test, ?QOS_1, <<"t">>, <<"payload">>),
-    {ok, [], Session} = emqx_session:publish(1, Msg, session()).
+    {ok, [], _Session} = emqx_session:publish(1, Msg, session()).
 
 t_publish_qos0(_) ->
     ok = meck:expect(emqx_broker, publish, fun(_) -> [] end),
     Msg = emqx_message:make(test, ?QOS_1, <<"t">>, <<"payload">>),
-    {ok, [], Session} = emqx_session:publish(0, Msg, session()).
+    {ok, [], _Session} = emqx_session:publish(0, Msg, session()).
 
 t_is_awaiting_full_false(_) ->
     ?assertNot(emqx_session:is_awaiting_full(session(#{max_awaiting_rel => 0}))).
@@ -196,7 +196,7 @@ t_pubcomp_id_not_found(_) ->
 %%--------------------------------------------------------------------
 
 t_dequeue(_) ->
-    {ok, Session} = emqx_session:dequeue(session()).
+    {ok, _Session} = emqx_session:dequeue(session()).
 
 t_deliver(_) ->
     Delivers = [delivery(?QOS_1, <<"t1">>), delivery(?QOS_2, <<"t2">>)],
@@ -222,7 +222,6 @@ t_takeover(_) ->
 
 t_resume(_) ->
     ok = meck:expect(emqx_broker, subscribe, fun(_, _, _) -> ok end),
-    Subs = #{<<"t">> => ?DEFAULT_SUBOPTS},
     Session = session(#{subscriptions => #{<<"t">> => ?DEFAULT_SUBOPTS}}),
     ok = emqx_session:resume(<<"clientid">>, Session).