Add mixedmode test back in

Signed-off-by: Derek Collison <derek@nats.io>

server/jetstream_cluster_test.go

@@ -5422,6 +5422,51 @@ func TestJetStreamClusterAckPendingWithMaxRedelivered(t *testing.T) {
 	})
 }
 
+func TestJetStreamClusterMixedMode(t *testing.T) {
+	c := createMixedModeCluster(t, "MM5", 3, 2)
+	defer c.shutdown()
+
+	// Client based API - Non-JS server.
+	nc, js := jsClientConnect(t, c.serverByName("S-5"))
+	defer nc.Close()
+
+	_, err := js.AddStream(&nats.StreamConfig{
+		Name:     "TEST",
+		Subjects: []string{"foo", "bar"},
+		Replicas: 3,
+	})
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	ml := c.leader()
+	if ml == nil {
+		t.Fatalf("No metaleader")
+	}
+
+	// Make sure we are tracking only the JS peers.
+	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
+		peers := ml.JetStreamClusterPeers()
+		if len(peers) == 3 {
+			return nil
+		}
+		return fmt.Errorf("Not correct number of peers, expected %d, got %d", 3, len(peers))
+	})
+
+	// Grab the underlying raft structure and make sure the system adjusts its cluster set size.
+	meta := ml.getJetStream().getMetaGroup().(*raft)
+	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
+		ps := meta.currentPeerState()
+		if len(ps.knownPeers) != 3 {
+			return fmt.Errorf("Expected known peers to be 3, but got %+v", ps.knownPeers)
+		}
+		if ps.clusterSize != 3 {
+			return fmt.Errorf("Expected cluster size to be 3, but got %+v", ps)
+		}
+		return nil
+	})
+}
+
 // Support functions
 
 // Used to setup superclusters for tests.
@@ -5695,6 +5740,47 @@ var jsClusterImportsTempl = `
 	}
 `
 
+func createMixedModeCluster(t *testing.T, clusterName string, numJsServers, numNonServers int) *cluster {
+	if clusterName == "" || numJsServers < 1 || numNonServers < 1 {
+		t.Fatalf("Bad params")
+	}
+
+	numServers := numJsServers + numNonServers
+	const startClusterPort = 23232
+
+	// Build out the routes that will be shared with all configs.
+	var routes []string
+	for cp := startClusterPort; cp < startClusterPort+numServers; cp++ {
+		routes = append(routes, fmt.Sprintf("nats-route://127.0.0.1:%d", cp))
+	}
+	routeConfig := strings.Join(routes, ",")
+
+	// Go ahead and build configurations and start servers.
+	c := &cluster{servers: make([]*Server, 0, numServers), opts: make([]*Options, 0, numServers), name: clusterName}
+
+	for cp := startClusterPort; cp < startClusterPort+numServers; cp++ {
+		storeDir := createDir(t, JetStreamStoreDir)
+		sn := fmt.Sprintf("S-%d", cp-startClusterPort+1)
+		conf := fmt.Sprintf(jsClusterLimitsTempl, sn, storeDir, clusterName, cp, routeConfig)
+
+		// Disable JS by commmenting it out.
+		if cp-startClusterPort >= numJsServers {
+			conf = strings.Replace(conf, "jetstream: ", "#jetstream: ", 1)
+		}
+
+		s, o := RunServerWithConfig(createConfFile(t, []byte(conf)))
+		c.servers = append(c.servers, s)
+		c.opts = append(c.opts, o)
+	}
+	c.t = t
+
+	// Wait til we are formed and have a leader.
+	c.checkClusterFormed()
+	c.waitOnPeerCount(numJsServers)
+
+	return c
+}
+
 // This will create a cluster that is explicitly configured for the routes, etc.
 // and also has a defined clustername. All configs for routes and cluster name will be the same.
 func createJetStreamClusterExplicit(t *testing.T, clusterName string, numServers int) *cluster {