Assure we manually close right socket in testcases

Concerning supervisor tests subtle issue. Before we just presumed that last
port in the global list of ports is the listening socket. From now we trace
the return value of the `ranch_tcp:listen` call.

test/acceptor_SUITE.erl

@@ -303,20 +303,29 @@ supervisor_clean_restart(_) ->
 	after 1000 -> ok end,
 	%% Verify that new children registered themselves properly.
 	ListenerPid = ranch_server:lookup_listener(Ref),
-	ok.
+	_ = erlang:trace(all, false, [all]),
+	ok = clean_traces().
 
 supervisor_clean_child_restart(_) ->
 	%% Then we verify that only parts of the supervision tree
 	%% restarted in the case of failure.
 	Ref = supervisor_clean_child_restart,
+	%% Trace socket allocations.
+	_ = erlang:trace(new, true, [call]),
+	1 = erlang:trace_pattern({ranch_tcp, listen, 1}, [{'_', [], [{return_trace}]}], [global]),
 	{ok, Pid} = ranch:start_listener(Ref,
 		1, ranch_tcp, [{port, 0}], echo_protocol, []),
 	%% Trace supervisor spawns.
 	1 = erlang:trace(Pid, true, [procs, set_on_spawn]),
 	ListenerPid0 = ranch_server:lookup_listener(Ref),
 	%% Manually shut the listening socket down.
-	Port = lists:last(erlang:ports()),
-	ok = gen_tcp:close(Port),
+	LSocket = receive
+		{trace, _, return_from, {ranch_tcp, listen, 1}, {ok, Socket}} ->
+			Socket
+	after 0 ->
+		error(lsocket_unknown)
+	end,
+	ok = gen_tcp:close(LSocket),
 	receive after 1000 -> ok end,
 	%% Verify that supervisor and its first two children are alive.
 	true = is_process_alive(Pid),
@@ -331,27 +340,48 @@ supervisor_clean_child_restart(_) ->
 	after 1000 -> ok end,
 	%% Verify that children still registered right.
 	ListenerPid0 = ranch_server:lookup_listener(Ref),
+	_ = erlang:trace_pattern({ranch_tcp, listen, 1}, false, []),
+	_ = erlang:trace(all, false, [all]),
+	ok = clean_traces(),
 	ok.
 
 supervisor_conns_alive(_) ->
 	%% And finally we make sure that in the case of partial failure
 	%% live connections are not being killed.
 	Ref = supervisor_conns_alive,
+	_ = erlang:trace(new, true, [call]),
+	1 = erlang:trace_pattern({ranch_tcp, listen, 1}, [{'_', [], [{return_trace}]}], [global]),
 	{ok, _} = ranch:start_listener(Ref,
 		1, ranch_tcp, [{port, 0}], remove_conn_and_wait_protocol, [{remove, false}]),
 	ok,
 	%% Get the listener socket
-	Port = lists:last(erlang:ports()),
+	LSocket = receive
+		{trace, _, return_from, {ranch_tcp, listen, 1}, {ok, S}} ->
+			S
+	after 0 ->
+		error(lsocket_unknown)
+	end,
 	TcpPort = ranch:get_port(Ref),
 	{ok, Socket} = gen_tcp:connect("localhost", TcpPort,
 		[binary, {active, true}, {packet, raw}]),
 	%% Shut the socket down
-	ok = gen_tcp:close(Port),
+	ok = gen_tcp:close(LSocket),
 	%% Assert that client is still viable.
 	receive {tcp_closed, _} -> error(closed) after 1500 -> ok end,
 	ok = gen_tcp:send(Socket, <<"poke">>),
-	receive {tcp_closed, _} -> ok end.
+	receive {tcp_closed, _} -> ok end,
+	_ = erlang:trace(all, false, [all]),
+	ok = clean_traces().
 
+clean_traces() ->
+	receive
+		{trace, _, _, _} ->
+			clean_traces();
+		{trace, _, _, _, _} ->
+			clean_traces()
+	after 0 ->
+		ok
+	end.
 
 %% Utility functions.