Fix flaky mem3_sync_event_listener EUnit testflaky-mem3-sync-eunit-fix

Config setting was asynchronous and the waiting function was not
waiting for the actual state value to change just that the state
function was returning.

The fix is to wait for the config value to propagate to the state.

1 files changed, 31 insertions, 8 deletions

diff --git a/src/mem3/src/mem3_sync_event_listener.erl b/src/mem3/src/mem3_sync_event_listener.erl
index e3368e23f..d7f745137 100644
--- a/src/mem3/src/mem3_sync_event_listener.erl
+++ b/src/mem3/src/mem3_sync_event_listener.erl
@@ -258,14 +258,16 @@ subscribe_for_config_test_() ->
 should_set_sync_delay(Pid) ->
     ?_test(begin
         config:set("mem3", "sync_delay", "123", false),
-        ?assertMatch(#state{delay = 123}, capture(Pid)),
+        wait_state_delay(Pid, 123),
+        ?assertMatch(#state{delay = 123}, get_state(Pid)),
         ok
     end).
 
 should_set_sync_frequency(Pid) ->
     ?_test(begin
         config:set("mem3", "sync_frequency", "456", false),
-        ?assertMatch(#state{frequency = 456}, capture(Pid)),
+        wait_state_frequency(Pid, 456),
+        ?assertMatch(#state{frequency = 456}, get_state(Pid)),
         ok
     end).
 
@@ -293,17 +295,38 @@ should_terminate(Pid) ->
         ok
     end).
 
-capture(Pid) ->
+
+get_state(Pid) ->
     Ref = make_ref(),
+    Pid ! {get_state, Ref, self()},
+    receive
+        {Ref, State} -> State
+    after 10 ->
+        timeout
+    end.
+
+
+wait_state_frequency(Pid, Val) ->
     WaitFun = fun() ->
-        Pid ! {get_state, Ref, self()},
-        receive
-            {Ref, State} -> State
-        after 0 ->
-            wait
+        case get_state(Pid) of
+            timeout ->
+                wait;
+            #state{frequency = Val} ->
+                true
         end
     end,
     test_util:wait(WaitFun).
 
 
+wait_state_delay(Pid, Val) ->
+    WaitFun = fun() ->
+        case get_state(Pid) of
+            timeout ->
+                wait;
+            #state{delay = Val} ->
+                true
+        end
+    end,
+    test_util:wait(WaitFun).
+
 -endif.