Applying this patch makes the tests pass for me, but I don't think the patch is appropriate (just hides the bug):

```
$ git diff
diff --git a/Lib/test/test_asyncio/test_unix_events.py b/Lib/test/test_asyncio/test_unix_events.py
index 5bd76d3..ff6c4e1 100644
--- a/Lib/test/test_asyncio/test_unix_events.py
+++ b/Lib/test/test_asyncio/test_unix_events.py
@@ -480,7 +480,7 @@ class SelectorEventLoopUnixSockSendfileTests(test_utils.TestCase):
         proto = self.MyProto(self.loop)
         port = support.find_unused_port()
         server = self.run_loop(self.loop.create_server(
-            lambda: proto, support.HOST, port))
+            lambda: proto, support.HOSTv4, port))
         self.run_loop(self.loop.sock_connect(sock, (support.HOST, port)))
 
         def cleanup():
```