test: verify listener leak is only emitted once

cjihrig · MylesBorins · commit 361bc845dc5d · 2017-07-11T17:43:47.000+01:00
When a possible listener leak is detected, a warning is emitted. This commit updates an existing test to verify that the warning is only emitted once. PR-URL: #12502 Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
diff --git a/test/parallel/test-event-emitter-max-listeners-warning.js b/test/parallel/test-event-emitter-max-listeners-warning.js
@@ -19,4 +19,5 @@ process.on('warning', common.mustCall((warning) => {
 }));
 
 e.on('event-type', function() {});
-e.on('event-type', function() {});
+e.on('event-type', function() {});  // Trigger warning.
+e.on('event-type', function() {});  // Verify that warning is emitted only once.
