chore: fix gateway authz cases

apps/emqx_gateway/test/emqx_gateway_auth_ct.erl

@@ -65,6 +65,15 @@
 
 -record(state, {}).
 
+-define(AUTHZ_HTTP_RESP(Result, Req),
+    cowboy_req:reply(
+        200,
+        #{<<"content-type">> => <<"application/json">>},
+        "{\"result\": \"" ++ atom_to_list(Result) ++ "\"}",
+        Req
+    )
+).
+
 %%------------------------------------------------------------------------------
 %% API
 %%------------------------------------------------------------------------------
@@ -169,12 +178,12 @@ on_start_auth(authz_http) ->
     Handler = fun(Req0, State) ->
         case cowboy_req:match_qs([topic, action, username], Req0) of
             #{topic := <<"/publish">>, action := <<"publish">>} ->
-                Req = cowboy_req:reply(200, Req0);
+                Req = ?AUTHZ_HTTP_RESP(allow, Req0);
             #{topic := <<"/subscribe">>, action := <<"subscribe">>} ->
-                Req = cowboy_req:reply(200, Req0);
+                Req = ?AUTHZ_HTTP_RESP(allow, Req0);
             %% for lwm2m
             #{username := <<"lwm2m">>} ->
-                Req = cowboy_req:reply(200, Req0);
+                Req = ?AUTHZ_HTTP_RESP(allow, Req0);
             _ ->
                 Req = cowboy_req:reply(400, Req0)
         end,