Randomly select traffic testcases

Since the number of configuration variants tested makes for (too) many.
Randomly select a subset of testcases in each configuration group.

2 files changed, 10 insertions, 13 deletions

diff --git a/lib/diameter/test/diameter_traffic_SUITE.erl b/lib/diameter/test/diameter_traffic_SUITE.erl
index 6aa3ffb7af..bb10638cd2 100644
--- a/lib/diameter/test/diameter_traffic_SUITE.erl
+++ b/lib/diameter/test/diameter_traffic_SUITE.erl
@@ -341,7 +341,11 @@ init_per_group(Name, Config) ->
                        server_strings = SD,
                        server_sender = SS,
                        server_throttle = ST},
-            [{group, G} | Config];
+            %% Limit the number of testcase, since the number of
+            %% groups is large.
+            All = ?util:scramble(tc()),
+            TCs = lists:sublist(All, rand:uniform(32)),
+            [{group, G}, {runlist, TCs} | Config];
         _ ->
             Config
     end.
@@ -359,12 +363,16 @@ end_per_group(_, _) ->
 
 %% Skip testcases that can reasonably fail under SCTP.
 init_per_testcase(Name, Config) ->
+    TCs = proplists:get_value(runlist, Config, []),
+    Run = [] == TCs orelse lists:member(Name, TCs),
     case [G || #group{transport = sctp} = G
                    <- [proplists:get_value(group, Config)]]
     of
         [_] when Name == send_maxlen;
                  Name == send_long ->
             {skip, sctp};
+        _ when not Run ->
+            {skip, random};
         _ ->
             [{testcase, Name} | Config]
     end.
diff --git a/lib/diameter/test/diameter_util.erl b/lib/diameter/test/diameter_util.erl
index 81b43913de..7266d3678c 100644
--- a/lib/diameter/test/diameter_util.erl
+++ b/lib/diameter/test/diameter_util.erl
@@ -173,18 +173,7 @@ recvl([{MRef, F} | L], Ref, Fun, Acc) ->
 %% Sort a list into random order.
 
 scramble(L) ->
-    foldl(fun(true, _, S, false) -> S end,
-          false,
-          [[fun s/1, L]]).
-
-s(L) ->
-    s([], L).
-
-s(Acc, []) ->
-    Acc;
-s(Acc, L) ->
-    {H, [T|Rest]} = lists:split(rand:uniform(length(L)) - 1, L),
-    s([T|Acc], H ++ Rest).
+    [X || {_,X} <- lists:sort([{rand:uniform(), T} || T <- L])].
 
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