inets: Fix handling of 'Content-Type' (httpc)

'Content-Type' is sent when it is explicitly set as a header or
there is a non-empty body in the request.

Former implementation dropped the explicit 'Content-Type' when
the request had an empty body.

Change-Id: I00a9e4a5011f9d28c04c0dfc5fe1561b1ab7eb09

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/inets/test/httpc_SUITE.erl b/lib/inets/test/httpc_SUITE.erl
index 3d375222b5..89a90b62f3 100644
--- a/lib/inets/test/httpc_SUITE.erl
+++ b/lib/inets/test/httpc_SUITE.erl
@@ -156,6 +156,7 @@ only_simulated() ->
      multipart_chunks,
      get_space,
      delete_no_body,
+     post_with_content_type,
      stream_fun_server_close
     ].
 
@@ -1550,6 +1551,15 @@ delete_no_body(Config) when is_list(Config) ->
         httpc:request(delete, {URL, [], "text/plain", "TEST"}, [], []).
 
 %%--------------------------------------------------------------------
+post_with_content_type(doc) ->
+    ["Test that a POST request with explicit 'Content-Type' does not drop the 'Content-Type' header - Solves ERL-736"];
+post_with_content_type(Config) when is_list(Config) ->
+    URL = url(group_name(Config), "/delete_no_body.html", Config),
+    %% Simulated server replies 500 if 'Content-Type' header is present
+    {ok, {{_,500,_}, _, _}} =
+        httpc:request(post, {URL, [], "application/x-www-form-urlencoded", ""}, [], []).
+
+%%--------------------------------------------------------------------
 request_options() ->
     [{doc, "Test http get request with socket options against local server (IPv6)"}].
 request_options(Config) when is_list(Config) ->