From aaad182ae6b1a00f20fe3f15c7d454109c42f6ec Mon Sep 17 00:00:00 2001
From: Tim Jensen <tim.l.jensen@gmail.com>
Date: Sat, 15 Dec 2018 16:24:03 -0600
Subject: [PATCH] Release app references in AsyncHTTPTestCase tearDown method
 (#2554)

Releasing the application and HTTP server references in tearDown helps
encourage the GC to clean up resources passed through the application
settings.
---
 tornado/test/testing_test.py | 18 ++++++++++++++++++
 tornado/testing.py           |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/tornado/test/testing_test.py b/tornado/test/testing_test.py
index 49f09a100..033eaf751 100644
--- a/tornado/test/testing_test.py
+++ b/tornado/test/testing_test.py
@@ -172,6 +172,24 @@ class SetUpTearDownTest(unittest.TestCase):
         self.assertEqual(expected, events)
 
 
+class AsyncHTTPTestCaseSetUpTearDownTest(unittest.TestCase):
+    def test_tear_down_releases_app_and_http_server(self):
+        result = unittest.TestResult()
+
+        class SetUpTearDown(AsyncHTTPTestCase):
+            def get_app(self):
+                return Application()
+
+            def test(self):
+                self.assertTrue(hasattr(self, "_app"))
+                self.assertTrue(hasattr(self, "http_server"))
+
+        test = SetUpTearDown("test")
+        test.run(result)
+        self.assertFalse(hasattr(test, "_app"))
+        self.assertFalse(hasattr(test, "http_server"))
+
+
 class GenTest(AsyncTestCase):
     def setUp(self):
         super(GenTest, self).setUp()
diff --git a/tornado/testing.py b/tornado/testing.py
index c8ae7712e..32c245bc1 100644
--- a/tornado/testing.py
+++ b/tornado/testing.py
@@ -432,6 +432,8 @@ class AsyncHTTPTestCase(AsyncTestCase):
             self.http_server.close_all_connections, timeout=get_async_test_timeout()
         )
         self.http_client.close()
+        del self.http_server
+        del self._app
         super(AsyncHTTPTestCase, self).tearDown()
 
 
-- 
2.47.2