diff --git a/openbsc/tests/db/db_test.c b/openbsc/tests/db/db_test.c
index dc81481..755a6e9 100644
--- a/openbsc/tests/db/db_test.c
+++ b/openbsc/tests/db/db_test.c
@@ -28,6 +28,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <inttypes.h>
 
 static struct gsm_network dummy_net;
@@ -159,12 +160,13 @@
 	subscr_put(rcv_subscr);
 }
 
-static void test_subs(const char *alice_imsi, char *imei1, char *imei2)
+static void test_subs(const char *imsi, char *imei1, char *imei2, bool make_ext)
 {
 	struct gsm_subscriber *alice = NULL, *alice_db;
 	char scratch_str[256];
 
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     make_ext);
 	db_subscriber_assoc_imei(alice, imei1);
 	if (imei2)
 		db_subscriber_assoc_imei(alice, imei2);
@@ -177,7 +179,7 @@
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	/* Get by IMSI */
-	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, alice_imsi);
+	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, imsi);
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	/* Get by id */
@@ -187,8 +189,14 @@
 	SUBSCR_PUT(alice_db);
 	/* Get by extension */
 	alice_db = db_get_subscriber(GSM_SUBSCRIBER_EXTENSION, alice->extension);
-	COMPARE(alice, alice_db);
-	SUBSCR_PUT(alice_db);
+	if (alice_db) {
+		if (!make_ext)
+			printf("FAIL: bogus extension created for IMSI %s\n",
+			       imsi);
+		COMPARE(alice, alice_db);
+		SUBSCR_PUT(alice_db);
+	} else if (make_ext)
+		printf("FAIL: no subscriber extension for IMSI %s\n", imsi);
 	SUBSCR_PUT(alice);
 }
 
@@ -217,18 +225,22 @@
 	struct gsm_subscriber *alice_db;
 
 	char *alice_imsi = "3243245432345";
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     true);
 	db_sync_subscriber(alice);
 	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, alice->imsi);
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	SUBSCR_PUT(alice);
 
-	test_subs("3693245423445", "1234567890", NULL);
-	test_subs("9993245423445", "1234567890", "6543560920");
+	test_subs("3693245423445", "1234567890", NULL, true);
+	test_subs("9993245423445", "1234567890", "6543560920", true);
+	test_subs("3123122223445", "1234567890", NULL, false);
+	test_subs("9123121223445", "1234567890", "6543560920", false);
 
 	/* create it again and see it fails */
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     true);
 	OSMO_ASSERT(!alice);
 
 	test_sms();
diff --git a/openbsc/tests/vty_test_runner.py b/openbsc/tests/vty_test_runner.py
index bae1866..23939e8 100644
--- a/openbsc/tests/vty_test_runner.py
+++ b/openbsc/tests/vty_test_runner.py
@@ -244,7 +244,7 @@
         self.vty.command("configure terminal")
         self.vty.command("nitb")
         self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
-        self.assertTrue(self.vty.verify("subscriber-create-on-demand regexp", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand no-extension", ['']))
         self.vty.command("end")
 
     def testSi2Q(self):
@@ -400,6 +400,9 @@
         self.vty.enable()
 
         imsi = "204300854013739"
+        imsi2 = "222301824913762"
+        imsi3 = "333500854113763"
+        imsi4 = "444583744053764"
 
         # Initially we don't have this subscriber
         self.vty.verify('show subscriber imsi '+imsi, ['% No subscriber found for imsi '+imsi])
@@ -407,14 +410,60 @@
         # Lets create one
         res = self.vty.command('subscriber create imsi '+imsi)
         self.assert_(res.find("    IMSI: "+imsi) > 0)
+        self.assert_(res.find("Extension") > 0)
 
         # Now we have it
         res = self.vty.command('show subscriber imsi '+imsi)
         self.assert_(res.find("    IMSI: "+imsi) > 0)
 
+        # With narrow random interval
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
+        # wrong interval
+        res = self.vty.command("subscriber-create-on-demand random 221 122")
+        # error string will contain arguments
+        self.assert_(res.find("122") > 0)
+        self.assert_(res.find("221") > 0)
+        # correct interval - silent ok
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand random 221 222", ['']))
+        self.vty.command("end")
+
+        res = self.vty.command('subscriber create imsi ' + imsi2)
+        self.assert_(res.find("    IMSI: " + imsi2) > 0)
+        self.assert_(res.find("221") > 0 or res.find("222") > 0)
+        self.assert_(res.find("    Extension: ") > 0)
+
+        # Without extension
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand no-extension", ['']))
+        self.vty.command("end")
+        res = self.vty.command('subscriber create imsi ' + imsi3)
+        self.assert_(res.find("    IMSI: " + imsi3) > 0)
+        self.assertEquals(res.find("Extension"), -1)
+
+        # With extension again
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("no subscriber-create-on-demand", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand random 221 666", ['']))
+        self.vty.command("end")
+
+        res = self.vty.command('subscriber create imsi ' + imsi4)
+        self.assert_(res.find("    IMSI: " + imsi4) > 0)
+        self.assert_(res.find("    Extension: ") > 0)
+
         # Delete it
         res = self.vty.command('subscriber imsi ' + imsi + ' delete')
         self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi2 + ' delete')
+        self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi3 + ' delete')
+        self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi4 + ' delete')
+        self.assert_("" == res)
 
         # Now it should not be there anymore
         res = self.vty.command('show subscriber imsi '+imsi)