1 files changed, 9 insertions, 4 deletions
diff --git a/Lib/test/test_asyncio/test_transports.py b/Lib/test/test_asyncio/test_transports.py
index 7de9b3e81a3..df448557a7b 100644
--- a/Lib/test/test_asyncio/test_transports.py
+++ b/Lib/test/test_asyncio/test_transports.py
@@ -22,14 +22,19 @@ class TransportTests(unittest.TestCase):
         self.assertIs(default, transport.get_extra_info('unknown', default))
 
     def test_writelines(self):
-        transport = asyncio.Transport()
-        transport.write = mock.Mock()
+        writer = mock.Mock()
+
+        class MyTransport(asyncio.Transport):
+            def write(self, data):
+                writer(data)
+
+        transport = MyTransport()
 
         transport.writelines([b'line1',
                               bytearray(b'line2'),
                               memoryview(b'line3')])
-        self.assertEqual(1, transport.write.call_count)
-        transport.write.assert_called_with(b'line1line2line3')
+        self.assertEqual(1, writer.call_count)
+        writer.assert_called_with(b'line1line2line3')
 
     def test_not_implemented(self):
         transport = asyncio.Transport()