added test for membership for join and leave topic

tests/pubsub/testgossipmembership.nim

@@ -22,7 +22,16 @@ import ../../libp2p/muxers/muxer
 import ../../libp2p/protocols/pubsub/rpc/protobuf
 import utils
 import chronos
+import unittest2, chronos, stew/byteutils, ../../libp2p/protocols/pubsub/gossipsub
+import ../helpers
+
+import sequtils, options, tables, sets, sugar
+import chronos, chronicles # Added chronicles for logging (trace)
+import stew/byteutils
+import chronos/ratelimit
+import metrics
 
+import ../../libp2p/protocols/pubsub/errors as pubsub_errors
 import ../helpers
 
 proc noop(data: seq[byte]) {.async: (raises: [CancelledError, LPStreamError]).} =
@@ -182,3 +191,78 @@ suite "GossipSub Topic Membership Tests":
 
     await allFuturesThrowing(conns.mapIt(it.close()))
     await gossipSub.switch.stop()
+
+  # Test for verifying peers joining a topic using `JOIN(topic)`
+  asyncTest "handle JOIN event":
+    let gossipSub = TestGossipSub.init(newStandardSwitch())
+
+    let topic = "test-join-topic"
+
+    # Initialize relevant data structures
+    gossipSub.mesh[topic] = initHashSet[PubSubPeer]()
+    gossipSub.topicParams[topic] = TopicParams.init()
+    gossipSub.gossipsub[topic] = initHashSet[PubSubPeer]()
+
+    var conns = newSeq[Connection]()
+
+    for i in 0 ..< 5:
+      let conn = TestBufferStream.new(noop)
+      conns &= conn
+      let peerId = randomPeerId()
+      conn.peerId = peerId
+      let peer = gossipSub.getPubSubPeer(peerId)
+      peer.sendConn = conn
+      gossipSub.gossipsub[topic].incl(peer)
+
+    # Simulate the peer joining the topic
+    gossipSub.PubSub.subscribe(
+      topic,
+      proc(topic: string, data: seq[byte]): Future[void] {.async.} =
+        discard
+      ,
+    )
+
+    check gossipSub.mesh[topic].len > 0 # Ensure the peer is added to the mesh
+    check gossipSub.topics.contains(topic) # Ensure the topic is in `topics`
+
+    await allFuturesThrowing(conns.mapIt(it.close()))
+    await gossipSub.switch.stop()
+
+  # Test for verifying peers leaving a topic using `LEAVE(topic)`
+  asyncTest "handle LEAVE event":
+    let gossipSub = TestGossipSub.init(newStandardSwitch())
+
+    let topic = "test-leave-topic"
+
+    # Initialize relevant data structures
+    gossipSub.mesh[topic] = initHashSet[PubSubPeer]()
+    gossipSub.topicParams[topic] = TopicParams.init()
+    gossipSub.gossipsub[topic] = initHashSet[PubSubPeer]()
+
+    var conns = newSeq[Connection]()
+
+    for i in 0 ..< 5:
+      let conn = TestBufferStream.new(noop)
+      conns &= conn
+      let peerId = randomPeerId()
+      conn.peerId = peerId
+      let peer = gossipSub.getPubSubPeer(peerId)
+      peer.sendConn = conn
+      gossipSub.gossipsub[topic].incl(peer)
+
+    # Simulate peer joining the topic first
+    gossipSub.PubSub.subscribe(
+      topic,
+      proc(topic: string, data: seq[byte]): Future[void] {.async.} =
+        discard
+      ,
+    )
+
+    # Now simulate peer leaving the topic
+    gossipSub.PubSub.unsubscribeAll(topic)
+
+    check topic notin gossipSub.mesh # Ensure the peer is removed from the mesh
+    check topic in gossipSub.gossipsub # Ensure the topic remains in `gossipsub`
+
+    await allFuturesThrowing(conns.mapIt(it.close()))
+    await gossipSub.switch.stop()