Initial work on the sys_SUITE

There's already tests failing and quite some refactoring to be
done to make some things easier to test or fix issues.

test/handlers/long_polling_sys_h.erl

@@ -0,0 +1,23 @@
+%% This module implements a loop handler that does nothing
+%% and expects a crash to happen.
+
+-module(long_polling_sys_h).
+
+-export([init/2]).
+-export([info/3]).
+-export([terminate/3]).
+
+init(Req, _) ->
+	process_flag(trap_exit, true),
+	erlang:send_after(500, self(), timeout),
+	{cowboy_loop, Req, undefined, hibernate}.
+
+info(timeout, Req, State) ->
+	%% Send an unused status code to make sure there's no
+	%% conflict with whatever Cowboy may send itself.
+	{ok, cowboy_req:reply(<<"299 OK!">>, Req), State};
+info(_, Req, State) ->
+	{ok, Req, State}.
+
+terminate({crash, _, _}, _, _) ->
+	ok.