cohttp-lwt-unix: fix test_sanity.exe

In the absence of an encoding in the headers,
Http.Response.Make now defaults to Unknown,
which makes the system hang unable to decide
how to get the body.

Signed-off-by: Marcello Seri <marcello.seri@gmail.com>

cohttp-lwt-unix/test/test_sanity.ml

@@ -48,12 +48,18 @@ let server =
       (fun _ _ ->
         Lwt.return
           (`Expert
-            ( Http.Response.make (),
-              fun _ic oc -> Lwt_io.write oc "8\r\nexpert 1\r\n0\r\n\r\n" )));
+            (let headers =
+               Http.(
+                 Header.add_transfer_encoding (Header.init ()) Transfer.Chunked)
+             in
+             ( Http.Response.make ~headers (),
+               fun _ic oc -> Lwt_io.write oc "8\r\nexpert 1\r\n0\r\n\r\n" ))));
       (fun _ _ ->
         Lwt.return
           (`Expert
-            ( Http.Response.make (),
+            ( (* Alternatively, cohttp.response.make injects the Chunked encoding when no
+                 encoding is already in the headers. *)
+              Cohttp.Response.make (),
               fun ic oc ->
                 Lwt_io.write oc "8\r\nexpert 2\r\n0\r\n\r\n" >>= fun () ->
                 Lwt_io.flush oc >>= fun () ->

cohttp-lwt-unix/test/test_sanity_noisy.ml

@@ -7,7 +7,7 @@ module Body = Cohttp_lwt.Body
 module IO = Cohttp_lwt_unix.Private.IO
 
 let chunk_body = [ "one"; ""; " "; "bar"; "" ]
-let () = Logs.set_level (Some Info)
+let () = Logs.set_level (Some Warning)
 let () = Logs.set_reporter Logs.nop_reporter
 
 let check_logs test () =