Add number of clusters alive to statistics, and add leak check to suite.

cluster.go

@@ -64,6 +64,7 @@ func newCluster(userSeeds []string, direct bool, dial dialer) *mongoCluster {
 	}
 	cluster.serverSynced.L = cluster.RWMutex.RLocker()
 	cluster.sync = make(chan bool, 1)
+	stats.cluster(+1)
 	go cluster.syncServersLoop()
 	return cluster
 }
@@ -91,6 +92,7 @@ func (cluster *mongoCluster) Release() {
 		}
 		// Wake up the sync loop so it can die.
 		cluster.syncServers()
+		stats.cluster(-1)
 	}
 	cluster.Unlock()
 }

stats.go

@@ -58,6 +58,7 @@ func ResetStats() {
 	old := stats
 	stats = &Stats{}
 	// These are absolute values:
+	stats.Clusters = old.Clusters
 	stats.SocketsInUse = old.SocketsInUse
 	stats.SocketsAlive = old.SocketsAlive
 	stats.SocketRefs = old.SocketRefs
@@ -66,6 +67,7 @@ func ResetStats() {
 }
 
 type Stats struct {
+	Clusters     int
 	MasterConns  int
 	SlaveConns   int
 	SentOps      int
@@ -76,6 +78,14 @@ type Stats struct {
 	SocketRefs   int
 }
 
+func (stats *Stats) cluster(delta int) {
+	if stats != nil {
+		statsMutex.Lock()
+		stats.Clusters += delta
+		statsMutex.Unlock()
+	}
+}
+
 func (stats *Stats) conn(delta int, master bool) {
 	if stats != nil {
 		statsMutex.Lock()

suite_test.go

@@ -110,15 +110,29 @@ func (s *S) TearDownTest(c *C) {
 			s.Thaw(host)
 		}
 	}
-	for i := 0; i < 20; i++ {
-		stats := mgo.GetStats()
+	var stats mgo.Stats
+	for i := 0; ; i++ {
+		stats = mgo.GetStats()
 		if stats.SocketsInUse == 0 && stats.SocketsAlive == 0 {
-			return
+			break
+		}
+		if i == 20 {
+			c.Fatal("Test left sockets in a dirty state")
 		}
 		c.Logf("Waiting for sockets to die: %d in use, %d alive", stats.SocketsInUse, stats.SocketsAlive)
 		time.Sleep(500 * time.Millisecond)
 	}
-	c.Fatal("Test left sockets in a dirty state")
+	for i := 0; ; i++ {
+		stats = mgo.GetStats()
+		if stats.Clusters == 0 {
+			break
+		}
+		if i == 60 {
+			c.Fatal("Test left clusters alive")
+		}
+		c.Logf("Waiting for clusters to die: %d alive", stats.Clusters)
+		time.Sleep(1 * time.Second)
+	}
 }
 
 func (s *S) Stop(host string) {