diff --git a/test/Makefile.am b/test/Makefile.am
index 526cfcf..5cce4c6 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -12,6 +12,7 @@ TESTS = run-test.sh
 TESTS_ENVIRONMENT = NO_MAKE=yes CUTTER="$(CUTTER)"
 
 noinst_LTLIBRARIES = \
+		     mifare_desfire_auto_authenticate.la \
 		     test_mad.la \
 		     test_mifare_application.la \
 		     test_mifare_classic.la \
@@ -26,6 +27,9 @@ noinst_LTLIBRARIES = \
 
 AM_LDFLAGS = -module -rpath $(libdir) -avoid-version -no-undefined
 
+mifare_desfire_auto_authenticate_la_SOURCES = mifare_desfire_auto_authenticate.c \
+						 mifare_desfire_auto_authenticate.h
+
 test_mad_la_SOURCES = test_mad.c
 test_mad_la_LIBADD = $(top_builddir)/libfreefare/libfreefare.la
 
@@ -47,7 +51,8 @@ test_mifare_classic_create_trailer_block_la_LIBADD = $(top_builddir)/libfreefare
 test_mifare_desfire_la_SOURCES = test_mifare_desfire.c \
 				 mifare_desfire_fixture.c \
 				 mifare_desfire_fixture.h
-test_mifare_desfire_la_LIBADD = $(top_builddir)/libfreefare/libfreefare.la -lutil
+test_mifare_desfire_la_LIBADD = $(top_builddir)/libfreefare/libfreefare.la \
+				mifare_desfire_auto_authenticate.lo
 
 test_mifare_desfire_aid_la_SOURCES = test_mifare_desfire_aid.c
 test_mifare_desfire_aid_la_LIBADD = $(top_builddir)/libfreefare/libfreefare.la
diff --git a/test/mifare_desfire_auto_authenticate.c b/test/mifare_desfire_auto_authenticate.c
new file mode 100644
index 0000000..35b2a00
--- /dev/null
+++ b/test/mifare_desfire_auto_authenticate.c
@@ -0,0 +1,61 @@
+/*-
+ * Copyright (C) 2010, Romain Tartiere.
+ * 
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ * 
+ * $Id$
+ */
+
+#include <cutter.h>
+
+#include <freefare.h>
+
+#include "mifare_desfire_auto_authenticate.h"
+
+uint8_t key_data_null[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+uint8_t key_data_des[8]   = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H' };
+uint8_t key_data_3des[16] = { 'C', 'a', 'r', 'd', ' ', 'M', 'a', 's', 't', 'e', 'r', ' ', 'K', 'e', 'y', '!' };
+
+void
+mifare_desfire_auto_authenticate (MifareTag tag, uint8_t key_no)
+{
+    /* Determine which key is currently the master one */
+    uint8_t key_version;
+    int res = mifare_desfire_get_key_version (tag, key_no, &key_version);
+    cut_assert_equal_int (0, res, cut_message ("mifare_desfire_get_key_version()"));
+
+    MifareDESFireKey key;
+
+    switch (key_version) {
+    case 0x00:
+	key = mifare_desfire_des_key_new_with_version (key_data_null);
+	break;
+    case 0xAA:
+	key = mifare_desfire_des_key_new_with_version (key_data_des);
+	break;
+    case 0xC7:
+	key = mifare_desfire_3des_key_new_with_version (key_data_3des);
+	break;
+    default:
+	cut_fail ("Unknown master key.");
+    }
+
+    cut_assert_not_null (key, cut_message ("Cannot allocate key"));
+
+    /* Authenticate with this key */
+    res = mifare_desfire_authenticate (tag, key_no, key);
+    cut_assert_equal_int (0, res, cut_message ("mifare_desfire_authenticate()"));
+
+    mifare_desfire_key_free (key);
+}
diff --git a/test/mifare_desfire_auto_authenticate.h b/test/mifare_desfire_auto_authenticate.h
new file mode 100644
index 0000000..5bec992
--- /dev/null
+++ b/test/mifare_desfire_auto_authenticate.h
@@ -0,0 +1,29 @@
+/*-
+ * Copyright (C) 2010, Romain Tartiere.
+ * 
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ * 
+ * $Id$
+ */
+
+#ifndef _MIFARE_DESFIRE_AUTO_AUTHENTICATE_H
+#define _MIFARE_DESFIRE_AUTO_AUTHENTICATE_H
+
+extern uint8_t key_data_null[8];
+extern uint8_t key_data_des[8];
+extern uint8_t key_data_3des[16];
+
+void		 mifare_desfire_auto_authenticate (MifareTag tag, uint8_t key_no);
+
+#endif
diff --git a/test/test_mifare_desfire.c b/test/test_mifare_desfire.c
index 40b5912..cd85d44 100644
--- a/test/test_mifare_desfire.c
+++ b/test/test_mifare_desfire.c
@@ -26,10 +26,7 @@
 #include "freefare_internal.h"
 
 #include "mifare_desfire_fixture.h"
-
-uint8_t key_data_null[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
-uint8_t key_data_des[8]   = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H' };
-uint8_t key_data_3des[16] = { 'C', 'a', 'r', 'd', ' ', 'M', 'a', 's', 't', 'e', 'r', ' ', 'K', 'e', 'y', '!' };
+#include "mifare_desfire_auto_authenticate.h"
 
 #define cut_assert_success(last_command) \
     do { \
@@ -52,34 +49,7 @@ test_mifare_desfire (void)
     res = mifare_desfire_get_version (tag, &version_info);
     cut_assert_success ("mifare_desfire_get_version()");
 
-    /* Determine which key is currently the master one */
-    uint8_t key_version;
-    res = mifare_desfire_get_key_version (tag, 0, &key_version);
-    cut_assert_success ("mifare_desfire_get_key_version()");
-
-    MifareDESFireKey key;
-
-    switch (key_version) {
-    case 0x00:
-	key = mifare_desfire_des_key_new_with_version (key_data_null);
-	break;
-    case 0xAA:
-	key = mifare_desfire_des_key_new_with_version (key_data_des);
-	break;
-    case 0xC7:
-	key = mifare_desfire_3des_key_new_with_version (key_data_3des);
-	break;
-    default:
-	cut_fail ("Unknown master key.");
-    }
-
-    cut_assert_not_null (key, cut_message ("Cannot allocate key"));
-
-    /* Authenticate with this key */
-    res = mifare_desfire_authenticate (tag, 0, key);
-    cut_assert_success ("mifare_desfire_authenticate()");
-
-    mifare_desfire_key_free (key);
+     mifare_desfire_auto_authenticate (tag, 0);
 
     /*
      * This unit test change key settings to more restrictive ones, so reset
@@ -89,10 +59,11 @@ test_mifare_desfire (void)
     cut_assert_success ("mifare_desfire_change_key_settings()");
 
     /* Change master key to DES */
-    key = mifare_desfire_des_key_new_with_version (key_data_des);
+    MifareDESFireKey key = mifare_desfire_des_key_new_with_version (key_data_des);
     mifare_desfire_change_key (tag, 0, key, NULL);
     cut_assert_success ("mifare_desfire_change_key()");
 
+    uint8_t key_version;
     res = mifare_desfire_get_key_version (tag, 0, &key_version);
     cut_assert_success ("mifare_desfire_get_key_version()");
     cut_assert_equal_int (0xAA, key_version, cut_message ("Wrong key_version value."));