QC test for backing queue fold

2 files changed, 22 insertions, 5 deletions

diff --git a/src/rabbit_backing_queue_qc.erl b/src/rabbit_backing_queue_qc.erl
index 3168ca5c..00e17d02 100644
--- a/src/rabbit_backing_queue_qc.erl
+++ b/src/rabbit_backing_queue_qc.erl
@@ -106,7 +106,8 @@ command(S) ->
                {1,  qc_dropwhile(S)},
                {1,  qc_is_empty(S)},
                {1,  qc_timeout(S)},
-               {1,  qc_purge(S)}]).
+               {1,  qc_purge(S)},
+               {1,  qc_fold(S)}]).
 
 qc_publish(#state{bqstate = BQ}) ->
     {call, ?BQMOD, publish,
@@ -157,6 +158,9 @@ qc_timeout(#state{bqstate = BQ}) ->
 qc_purge(#state{bqstate = BQ}) ->
     {call, ?BQMOD, purge, [BQ]}.
 
+qc_fold(#state{bqstate = BQ}) ->
+    {call, ?BQMOD, fold, [fun foldfun/2, foldacc(), BQ]}.
+
 %% Preconditions
 
 %% Create long queues by only allowing publishing
@@ -271,7 +275,11 @@ next_state(S, BQ, {call, ?MODULE, timeout, _Args}) ->
 
 next_state(S, Res, {call, ?BQMOD, purge, _Args}) ->
     BQ1 = {call, erlang, element, [2, Res]},
-    S#state{bqstate = BQ1, len = 0, messages = gb_trees:empty()}.
+    S#state{bqstate = BQ1, len = 0, messages = gb_trees:empty()};
+
+next_state(S, Res, {call, ?BQMOD, fold, _Args}) ->
+    BQ1 = {call, erlang, element, [2, Res]},
+    S#state{bqstate = BQ1}.
 
 %% Postconditions
 
@@ -321,6 +329,12 @@ postcondition(S, {call, ?BQMOD, drain_confirmed, _Args}, Res) ->
     lists:all(fun (M) -> gb_sets:is_element(M, Confirms) end,
               ReportedConfirmed);
 
+postcondition(S, {call, ?BQMOD, fold, _Args}, {Res, _BQ}) ->
+    #state{messages = Messages} = S,
+    lists:foldl(fun ({_SeqId, {_MsgProps, Msg}}, Acc) ->
+                        foldfun(Msg, Acc)
+                end, foldacc(), gb_trees:to_list(Messages)) =:= Res;
+
 postcondition(#state{bqstate = BQ, len = Len}, {call, _M, _F, _A}, _Res) ->
     ?BQMOD:len(BQ) =:= Len.
 
@@ -379,6 +393,9 @@ rand_choice(List, Selection, N)  ->
                        rand_choice(List -- [Picked], [Picked | Selection],
                        N - 1).
 
+foldfun(Msg, Acc) -> [Msg | Acc].
+foldacc() -> [].
+
 dropfun(Props) ->
     Expiry = eval({call, erlang, element,
                    [?RECORD_INDEX(expiry, message_properties), Props]}),
diff --git a/src/rabbit_variable_queue.erl b/src/rabbit_variable_queue.erl
index 7636d5ea..f49aa085 100644
--- a/src/rabbit_variable_queue.erl
+++ b/src/rabbit_variable_queue.erl
@@ -18,8 +18,8 @@
 
 -export([init/3, terminate/2, delete_and_terminate/2, purge/1,
          publish/4, publish_delivered/4, discard/3, drain_confirmed/1,
-         dropwhile/3, fetch/2, drop/2, ack/2, requeue/2, len/1, is_empty/1,
-         depth/1, set_ram_duration_target/2, ram_duration/1,
+         dropwhile/3, fetch/2, drop/2, ack/2, requeue/2, fold/3, len/1,
+         is_empty/1, depth/1, set_ram_duration_target/2, ram_duration/1,
          needs_timeout/1, timeout/1, handle_pre_hibernate/1, status/1, invoke/3,
          is_duplicate/2, multiple_routing_keys/0, foreach_ack/3]).
 
@@ -684,7 +684,7 @@ fold(Fun, Acc, #vqstate { q1    = Q1,
                           q3    = Q3,
                           q4    = Q4} = State) ->
     QFun = fun(M, {A, S}) ->
-                   {#msg_status{msg = Msg}, State1} = read_msg(M, S, false),
+                   {#msg_status{msg = Msg}, State1} = read_msg(M, false, S),
                    A1 = Fun(Msg, A),
                    {A1, State1}
            end,