diff --git a/testing/mozharness/test/test_base_script.py b/testing/mozharness/test/test_base_script.py
index 67118a0fa9e6..1e2e22c606e7 100644
--- a/testing/mozharness/test/test_base_script.py
+++ b/testing/mozharness/test/test_base_script.py
@@ -704,7 +704,7 @@ class TestScriptDecorators(unittest.TestCase):
         self.assertEqual(len(self.s._listeners['pre_run']), 1)
         self.assertEqual(len(self.s._listeners['pre_action']), 3)
         self.assertEqual(len(self.s._listeners['post_action']), 3)
-        self.assertEqual(len(self.s._listeners['post_run']), 2)
+        self.assertEqual(len(self.s._listeners['post_run']), 3)
 
     def test_pre_post_fired(self):
         self.s = BaseScriptWithDecorators(initial_config_file='test/test.json')