Index: uspace/app/tmon/list.c
===================================================================
--- uspace/app/tmon/list.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
+++ uspace/app/tmon/list.c	(revision 0f816af61635af65bf455478b6e2d148e1f7c7ad)
@@ -39,6 +39,4 @@
 #include <loc.h>
 #include <usb/diag/diag.h>
-#include <usb/diag/iface.h>
-#include <errno.h>
 #include "commands.h"
 
Index: uspace/app/tmon/test.c
===================================================================
--- uspace/app/tmon/test.c	(revision 2bd04b29894a0891b539a1820a4e9c90d026c438)
+++ uspace/app/tmon/test.c	(revision 0f816af61635af65bf455478b6e2d148e1f7c7ad)
@@ -41,4 +41,5 @@
 #include <str_error.h>
 #include <usb/diag/diag.h>
+#include <usb/diag/iface.h>
 #include "commands.h"
 
@@ -115,5 +116,19 @@
 
 static int bulk_worker(devman_handle_t fun) {
+	async_sess_t *sess = usb_diag_connect(fun);
+	async_exch_t *exch = async_exchange_begin(sess);
+
 	// TODO: do some testing
+	int y;
+	int rc = usb_diag_test(exch, 4200, &y);
+
+	if (rc) {
+		printf(NAME ": %s\n", str_error(rc));
+	} else {
+		printf("The number is %d.\n", y);
+	}
+
+	async_exchange_end(exch);
+	usb_diag_disconnect(sess);
 	return 0;
 }