Add tests for charsets_provided

Fix cases where the q-value is 0 and where a wildcard
was sent in the accept-charset header.

Also don't send a charset in the content-type of the
response if the media type is not text.

Thanks to Philip Witty for help figuring this out.

test/handlers/charsets_provided_empty_h.erl

@@ -0,0 +1,30 @@
+%% This module has a text and non-text media type,
+%% but provides no charset. All requests will result
+%% in a 406 not acceptable.
+
+-module(charsets_provided_empty_h).
+
+-export([init/2]).
+-export([content_types_provided/2]).
+-export([charsets_provided/2]).
+-export([get_text_plain/2]).
+-export([get_application_json/2]).
+
+init(Req, Opts) ->
+	{cowboy_rest, Req, Opts}.
+
+content_types_provided(Req, State) ->
+	{[
+		{{<<"text">>, <<"plain">>, []}, get_text_plain},
+		{{<<"application">>, <<"json">>, []}, get_application_json}
+	], Req, State}.
+
+charsets_provided(Req, State) ->
+	{[], Req, State}.
+
+get_text_plain(Req, State) ->
+	{<<"This is REST!">>, Req, State}.
+
+get_application_json(Req, State) ->
+	{<<"{\"hello\": \"rest\"}">>, Req, State}.
+

test/handlers/charsets_provided_h.erl

@@ -0,0 +1,28 @@
+%% This module has a text and non-text media type,
+%% and provides two charsets.
+
+-module(charsets_provided_h).
+
+-export([init/2]).
+-export([content_types_provided/2]).
+-export([charsets_provided/2]).
+-export([get_text_plain/2]).
+-export([get_application_json/2]).
+
+init(Req, Opts) ->
+	{cowboy_rest, Req, Opts}.
+
+content_types_provided(Req, State) ->
+	{[
+		{{<<"text">>, <<"plain">>, []}, get_text_plain},
+		{{<<"application">>, <<"json">>, []}, get_application_json}
+	], Req, State}.
+
+charsets_provided(Req, State) ->
+	{[<<"utf-8">>, <<"utf-16">>], Req, State}.
+
+get_text_plain(Req, State) ->
+	{<<"This is REST!">>, Req, State}.
+
+get_application_json(Req, State) ->
+	{<<"{\"hello\": \"rest\"}">>, Req, State}.