diff --git a/testing/test_unittest.py b/testing/test_unittest.py
index 39a31cfea..1390ed95c 100644
--- a/testing/test_unittest.py
+++ b/testing/test_unittest.py
@@ -616,6 +616,7 @@ def test_unittest_expected_failure_for_passing_test_is_fail(testdir):
     result.stdout.fnmatch_lines([
         "*FAILURES*",
         "*MyTestCase*test_passing_test_is_fail*",
+        "*Unexpected success*",
         "*1 failed*",
     ])
     assert result.ret == 1