test: add test for a unref'ed timer leak

PR-URL: #1330
Reviewed-by: Trevor Norris <[email protected]>

Author: indutny

test/parallel/test-timers-unref-leak.js

@@ -0,0 +1,25 @@
+var assert = require('assert');
+
+var called = 0;
+var closed = 0;
+
+var timeout = setTimeout(function() {
+  called++;
+}, 10);
+timeout.unref();
+
+// Wrap `close` method to check if the handle was closed
+var close = timeout._handle.close;
+timeout._handle.close = function() {
+  closed++;
+  return close.apply(this, arguments);
+};
+
+// Just to keep process alive and let previous timer's handle die
+setTimeout(function() {
+}, 50);
+
+process.on('exit', function() {
+  assert.equal(called, 1);
+  assert.equal(closed, 1);
+});