2 files changed, 64 insertions, 3 deletions

diff --git a/tests/integration/harness.py b/tests/integration/harness.py
index a9d38ca..10aa6de 100644
--- a/tests/integration/harness.py
+++ b/tests/integration/harness.py
@@ -192,7 +192,7 @@ class Tracker:
     def torrent_count(self):
         return int(self.stats("torr").split()[0])
 
-    def livesync_send(self, payload):
+    def livesync_send(self, payload, group=LIVESYNC_GROUP):
         """Put a packet on the live sync group.
 
         It has to go to the group rather than straight at the port: the
@@ -204,7 +204,7 @@ class Tracker:
             sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, socket.inet_aton("127.0.0.1"))
             sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
             sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 1)
-            sock.sendto(payload, (LIVESYNC_GROUP, self.livesync_port))
+            sock.sendto(payload, (group, self.livesync_port))
         finally:
             sock.close()
 
diff --git a/tests/integration/test_livesync.py b/tests/integration/test_livesync.py
index 3a9ee58..f4cb2db 100644
--- a/tests/integration/test_livesync.py
+++ b/tests/integration/test_livesync.py
@@ -10,7 +10,7 @@ import struct
 import subprocess
 import unittest
 
-from harness import TRACKER, TrackerTestCase
+from harness import TRACKER, Tracker, TrackerTestCase
 
 # enum { OT_SYNC_PEER4, OT_SYNC_PEER6 } in src/ot_livesync.c
 SYNC_PEER4 = 0
@@ -164,3 +164,64 @@ class LiveSyncUnconfigured(TrackerTestCase):
         for i in range(200):
             self.tracker.announce(self.hash_for("no-cluster-%d" % i), port=6881 + i, left=0)
         self.assertEqual(self.tracker.torrent_count(), 200)
+
+
+# RFC 2365 sets 239.192.0.0/14 aside for exactly this kind of use
+OWN_GROUP = "239.192.0.7"
+# A group nothing in this suite ever joins. Deliberately not the default one:
+# other trackers here do join that, on ports the harness picks at random, and
+# a socket bound to the wildcard address shares a port's multicast traffic
+# with anything else on the host that has joined the group it is addressed
+# to. Two clusters sharing a host and a port is pathological in the field but
+# routine in a test suite.
+UNJOINED_GROUP = "239.192.0.99"
+
+
+@unittest.skipUnless(has_livesync(), "this build has no WANT_SYNC_LIVE")
+class LiveSyncGroup(TrackerTestCase):
+    config = ("livesync.cluster.group %s\n"
+              "livesync.cluster.listen 127.0.0.1:{livesync_port}\n"
+              "livesync.cluster.node_ip 127.0.0.1\n" % OWN_GROUP)
+
+    def test_the_configured_group_is_joined(self):
+        info_hash = self.hash_for("own-group")
+        self.tracker.livesync_send(packet(SYNC_PEER4, [(info_hash, peer4("10.1.3.1", 6881, FLAG_SEEDING))]),
+                                   group=OWN_GROUP)
+        self.assertTrue(self.tracker.wait_until(lambda: self.tracker.torrent_count() == 1))
+
+    def test_another_group_is_left_alone(self):
+        """A cluster that picked its own group hears nothing from the others."""
+        info_hash = self.hash_for("not-our-group")
+        self.tracker.livesync_send(packet(SYNC_PEER4, [(info_hash, peer4("10.1.3.2", 6881, FLAG_SEEDING))]),
+                                   group=UNJOINED_GROUP)
+        self.assertFalse(self.tracker.wait_until(lambda: self.tracker.torrent_count() != 0, timeout=1))
+
+
+@unittest.skipUnless(has_livesync(), "this build has no WANT_SYNC_LIVE")
+class LiveSyncGroupRefused(unittest.TestCase):
+    """A cluster that asked for a group of its own must not quietly end up on
+    the one every other opentracker is on, so a line that does not name a
+    group stops the tracker rather than falling back."""
+
+    def start_with(self, group):
+        return Tracker("livesync.cluster.group %s\n"
+                       "livesync.cluster.listen 127.0.0.1:{livesync_port}\n"
+                       "livesync.cluster.node_ip 127.0.0.1\n" % group)
+
+    def test_a_unicast_address_stops_the_tracker(self):
+        with self.assertRaises(AssertionError) as caught:
+            self.start_with("10.0.0.1")
+        self.assertIn("multicast address", str(caught.exception))
+
+    def test_so_does_something_that_is_not_an_address(self):
+        with self.assertRaises(AssertionError) as caught:
+            self.start_with("not-an-address")
+        self.assertIn("multicast address", str(caught.exception))
+
+    def test_a_group_at_either_end_of_the_range_is_taken(self):
+        for group in ("224.0.0.1", "239.255.255.255"):
+            tracker = self.start_with(group)
+            try:
+                self.assertEqual(tracker.torrent_count(), 0)
+            finally:
+                tracker.stop()