Add deprecation test to get coverage up

Author: njsmith

trio/tests/test_ssl.py

@@ -1244,3 +1244,15 @@ async def setup(**kwargs):
     await aclose_forcefully(ssl_listener)
     await aclose_forcefully(ssl_client)
     await aclose_forcefully(ssl_server)
+
+
+async def test_deprecated_max_refill_bytes():
+    stream1, stream2 = memory_stream_pair()
+    with pytest.warns(trio.TrioDeprecationWarning):
+        SSLStream(stream1, CLIENT_CTX, max_refill_bytes=100)
+    with pytest.warns(trio.TrioDeprecationWarning):
+        # passing None is wrong here, but I'm too lazy to make a fake Listener
+        # and we get away with it for now. And this test will be deleted in a
+        # release or two anyway, so hopefully we'll keep getting away with it
+        # for long enough.
+        SSLListener(None, CLIENT_CTX, max_refill_bytes=100)