Add tests for leak errors

Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py

Index: Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py
diff --git a/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py b/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py
index 1bf13fb5308ea4d6f3358d9931c608330e887e41..9ac57dfc9e3ae304b9c7cb5804de4c3b7697bbfd 100644
--- a/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py
+++ b/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests_integrationtest.py
@@ -692,6 +692,12 @@ class RunTest(unittest.TestCase, StreamTestingMixin):
         self.assertEqual(details.exit_code, 1)
         self.assertTrue('Retrying' in err.getvalue())
 
+    def test_retrying_leak_tests(self):
+        host = MockHost()
+        details, err, _ = logging_run(['--retry-failures', 'failures/unexpected/leak.html'], tests_included=True, host=host)
+        self.assertEqual(details.exit_code, 1)
+        self.assertTrue('Retrying' in err.getvalue())
+
     def test_retrying_force_pixel_tests(self):
         host = MockHost()
         details, err, _ = logging_run(['--no-pixel-tests', '--retry-failures', 'failures/unexpected/text-image-checksum.html'], tests_included=True, host=host)