Add comments to test

Author: acogoluegnes

deps/rabbitmq_stomp/test/system_SUITE.erl

@@ -322,13 +322,15 @@ stream_filtering(Config) ->
     Version = ?config(version, Config),
     Client = ?config(stomp_client, Config),
     Stream = atom_to_list(?FUNCTION_NAME) ++ "-" ++ integer_to_list(rand:uniform(10000)),
+    %% subscription just to create the stream from STOMP
     SubDestination = "/topic/stream-queue-test",
     rabbit_stomp_client:send(
       Client, "SUBSCRIBE",
       [{"destination", SubDestination},
        {"receipt", "foo"},
        {"x-queue-name", Stream},
        {"x-queue-type", "stream"},
+       {?HEADER_X_STREAM_FILTER_SIZE_BYTES, "32"},
        {"durable", "true"},
        {"auto-delete", "false"},
        {"id", "1234"},
@@ -341,7 +343,12 @@ stream_filtering(Config) ->
                                {"receipt", "bar"}]),
     {ok, Client2, _, _} = stomp_receive(Client1, "RECEIPT"),
 
+    %% we are going to publish several waves of messages with and without filter values.
+    %% we will then create subscriptions with various filter options
+    %% and make sure we receive only what we asked for and not all the messages.
+
     StreamDestination = "/amq/queue/" ++ Stream,
+    %% logic to publish a wave of messages with or without a filter value
     WaveCount = 1000,
     Publish =
     fun(C, FilterValue) ->
@@ -360,11 +367,14 @@ stream_filtering(Config) ->
                                 C1
                         end, C, lists:seq(1, WaveCount))
     end,
+    %% publishing messages with the "apple" filter value
     Client3 = Publish(Client2, "apple"),
+    %% publishing messages with no filter value
     Client4 = Publish(Client3, undefined),
+    %% publishing messages with the "orange" filter value
     Client5 = Publish(Client4, "orange"),
 
-    %% one filter
+    %% filtering on "apple"
     rabbit_stomp_client:send(
       Client5, "SUBSCRIBE",
       [{"destination", StreamDestination},
@@ -374,19 +384,22 @@ stream_filtering(Config) ->
        {"x-stream-filter", "apple"},
        {"x-stream-offset", "first"}]),
     {Client6, AppleMessages} = stomp_receive_messages(Client5, Version),
+    %% we should get less than all the waves combined
     ?assert(length(AppleMessages) < WaveCount * 3),
+    %% client-side filtering
     AppleFilteredMessages =
     lists:filter(fun(H) ->
                          proplists:get_value("x-stream-filter-value", H) =:= "apple"
                  end, AppleMessages),
+    %% we should have only the "apple" messages
     ?assert(length(AppleFilteredMessages) =:= WaveCount),
     rabbit_stomp_client:send(
       Client6, "UNSUBSCRIBE", [{"destination", StreamDestination},
                                {"id", "0"},
                                {"receipt", "bar"}]),
     {ok, Client7, _, _} = stomp_receive(Client6, "RECEIPT"),
 
-    %% two filters
+    %% filtering on "apple" and "orange"
     rabbit_stomp_client:send(
       Client7, "SUBSCRIBE",
       [{"destination", StreamDestination},
@@ -396,20 +409,23 @@ stream_filtering(Config) ->
        {"x-stream-filter", "apple,orange"},
        {"x-stream-offset", "first"}]),
     {Client8, AppleOrangeMessages} = stomp_receive_messages(Client7, Version),
+    %% we should get less than all the waves combined
     ?assert(length(AppleOrangeMessages) < WaveCount * 3),
+    %% client-side filtering
     AppleOrangeFilteredMessages =
     lists:filter(fun(H) ->
                          proplists:get_value("x-stream-filter-value", H) =:= "apple" orelse
                          proplists:get_value("x-stream-filter-value", H) =:= "orange"
                  end, AppleOrangeMessages),
+    %% we should have only the "apple" and "orange" messages
     ?assert(length(AppleOrangeFilteredMessages) =:= WaveCount * 2),
     rabbit_stomp_client:send(
       Client8, "UNSUBSCRIBE", [{"destination", StreamDestination},
                                {"id", "0"},
                                {"receipt", "bar"}]),
     {ok, Client9, _, _} = stomp_receive(Client8, "RECEIPT"),
 
-    %% one filter and unfiltered
+    %% filtering on "apple" and messages without a filter value
     rabbit_stomp_client:send(
       Client9, "SUBSCRIBE",
       [{"destination", StreamDestination},
@@ -420,12 +436,15 @@ stream_filtering(Config) ->
        {"x-stream-match-unfiltered", "true"},
        {"x-stream-offset", "first"}]),
     {Client10, AppleUnfilteredMessages} = stomp_receive_messages(Client9, Version),
+    %% we should get less than all the waves combined
     ?assert(length(AppleUnfilteredMessages) < WaveCount * 3),
+    %% client-side filtering
     AppleUnfilteredFilteredMessages =
     lists:filter(fun(H) ->
                          proplists:get_value("x-stream-filter-value", H) =:= "apple" orelse
                          proplists:get_value("x-stream-filter-value", H) =:= undefined
                  end, AppleUnfilteredMessages),
+    %% we should have only the "apple" messages and messages without a filter value
     ?assert(length(AppleUnfilteredFilteredMessages) =:= WaveCount * 2),
     rabbit_stomp_client:send(
       Client10, "UNSUBSCRIBE", [{"destination", StreamDestination},