Add a test suite for RFC7538; update Cowlib to 2.2.0

This adds the 308 status code and fixes a few small
parsing bugs.

test/rfc7538_SUITE.erl

@@ -0,0 +1,52 @@
+%% Copyright (c) 2018, Loïc Hoguin <essen@ninenines.eu>
+%%
+%% Permission to use, copy, modify, and/or distribute this software for any
+%% purpose with or without fee is hereby granted, provided that the above
+%% copyright notice and this permission notice appear in all copies.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+-module(rfc7538_SUITE).
+-compile(export_all).
+-compile(nowarn_export_all).
+
+-import(ct_helper, [config/2]).
+-import(ct_helper, [doc/1]).
+-import(cowboy_test, [gun_open/1]).
+
+all() ->
+	cowboy_test:common_all().
+
+groups() ->
+	cowboy_test:common_groups(ct_helper:all(?MODULE)).
+
+init_per_group(Name, Config) ->
+	cowboy_test:init_common_groups(Name, Config, ?MODULE).
+
+end_per_group(Name, _) ->
+	cowboy:stop_listener(Name).
+
+init_dispatch(_) ->
+	cowboy_router:compile([{"[...]", [
+		{"/resp/:key[/:arg]", resp_h, []}
+	]}]).
+
+status_code_308(Config) ->
+	doc("The 308 Permanent Redirect status code can be sent. (RFC7538 3)"),
+	ConnPid = gun_open(Config),
+	Ref = gun:get(ConnPid, "/resp/reply2/308", [
+		{<<"accept-encoding">>, <<"gzip">>}
+	]),
+	{response, _, 308, _} = gun:await(ConnPid, Ref),
+	ok.
+
+%% @todo
+%   The server SHOULD generate a Location header field ([RFC7231],
+%   Section 7.1.2) in the response containing a preferred URI reference
+%   for the new permanent URI.