diff --git a/test/plugin/test_out_exec_filter.rb b/test/plugin/test_out_exec_filter.rb
index 5a7dc71044..21b570e1ca 100644
--- a/test/plugin/test_out_exec_filter.rb
+++ b/test/plugin/test_out_exec_filter.rb
@@ -504,6 +504,7 @@ def create_driver(conf)
     d.run(default_tag: 'test', expect_emits: 1, timeout: 10, start: false, shutdown: false){ d.feed(time, {"k1" => 1}) }
     d.run(default_tag: 'test', expect_emits: 1, timeout: 10, start: false, shutdown: false){ d.feed(time, {"k1" => 2}) }
     d.run(default_tag: 'test', expect_emits: 1, timeout: 10, start: false, shutdown: false){ d.feed(time, {"k1" => 3}) }
+    waiting(5) { sleep 0.1 until d.emit_count == 4 }
 
     assert_equal "2011-01-02 13:14:15\ttest\t0\n", d.formatted[0]
     assert_equal "2011-01-02 13:14:15\ttest\t1\n", d.formatted[1]