test_request: use correct user-agent

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

cohttp/test/test_request.ml

@@ -2,6 +2,8 @@ open Cohttp
 module String_io = Cohttp.Private.String_io
 module StringRequest = Request.Private.Make (String_io.M)
 
+let user_agent = Cohttp.Header.user_agent
+
 let uri_userinfo = Uri.of_string "http://foo:bar%2525@ocaml.org"
 
 let header_auth =
@@ -310,21 +312,22 @@ let null_content_length_header () =
   let () =
     (* The user-agent in releases contentsontains the version, we need to strip
        it for the test *)
-    let headers = Cohttp.Header.of_list [ ("user-agent", "ocaml-cohttp") ] in
     let r =
-      Cohttp.Request.make_for_client ~headers ~chunked:false ~body_length:0L
+      Cohttp.Request.make_for_client ~chunked:false ~body_length:0L
         `PUT
         (Uri.of_string "http://someuri.com")
     in
     Request.write_header r output
-  in
-  Alcotest.(check string)
-    "null content-length header are sent"
-    "PUT / HTTP/1.1\r\n\
-     user-agent: ocaml-cohttp\r\n\
+  in 
+  let expected = "PUT / HTTP/1.1\r\n\
      host: someuri.com\r\n\
+     user-agent: " ^ user_agent ^ "\r\n\
      content-length: 0\r\n\
      \r\n"
+  in
+  Alcotest.(check string)
+    "null content-length header are sent"
+    expected
     (Buffer.to_string output)
 
 let useless_null_content_length_header () =
@@ -336,9 +339,14 @@ let useless_null_content_length_header () =
     in
     Request.write_header r output
   in
+  let expected = "GET / HTTP/1.1\r\n\
+     host: someuri.com\r\n\
+     user-agent: " ^ user_agent ^ "\r\n\
+     \r\n"
+  in
   Alcotest.(check string)
     "null content-length header are not sent for bodyless methods"
-    "GET / HTTP/1.1\r\nhost: someuri.com\r\nuser-agent: ocaml-cohttp/\r\n\r\n"
+    expected
     (Buffer.to_string output)
 
 let () =