1 files changed, 5 insertions, 3 deletions
diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py
index a6cfcbf..aa39779 100644
--- a/Lib/test/test_asyncio/test_streams.py
+++ b/Lib/test/test_asyncio/test_streams.py
@@ -444,12 +444,14 @@ class StreamTests(test_utils.TestCase):
 
     def test_readuntil_eof(self):
         stream = asyncio.StreamReader(loop=self.loop)
-        stream.feed_data(b'some dataAA')
+        data = b'some dataAA'
+        stream.feed_data(data)
         stream.feed_eof()
 
-        with self.assertRaises(asyncio.IncompleteReadError) as cm:
+        with self.assertRaisesRegex(asyncio.IncompleteReadError,
+                                    'undefined expected bytes') as cm:
             self.loop.run_until_complete(stream.readuntil(b'AAA'))
-        self.assertEqual(cm.exception.partial, b'some dataAA')
+        self.assertEqual(cm.exception.partial, data)
         self.assertIsNone(cm.exception.expected)
         self.assertEqual(b'', stream._buffer)