add test

Signed-off-by: lhy1024 <admin@liudos.us>

pkg/election/leadership.go

@@ -188,6 +188,10 @@ func (ls *Leadership) Watch(serverCtx context.Context, revision int64) {
 		return
 	}
 
+	unhealthyTimeout := watchLoopUnhealthyTimeout
+	failpoint.Inject("fastTick", func() {
+		unhealthyTimeout = 5 * time.Second
+	})
 	ticker := time.NewTicker(etcdutil.RequestProgressInterval)
 	defer ticker.Stop()
 	lastReceivedResponseTime := time.Now()
@@ -213,7 +217,7 @@ func (ls *Leadership) Watch(serverCtx context.Context, revision int64) {
 		// When etcd is not available, the watcher.Watch will block,
 		// so we check the etcd availability first.
 		if !etcdutil.IsHealthy(serverCtx, ls.client) {
-			if time.Since(lastReceivedResponseTime) > watchLoopUnhealthyTimeout {
+			if time.Since(lastReceivedResponseTime) > unhealthyTimeout {
 				log.Error("the connect of leadership watcher is unhealthy",
 					zap.Int64("revision", revision),
 					zap.String("leader-key", ls.leaderKey),

pkg/election/leadership_test.go

@@ -16,6 +16,7 @@ package election
 
 import (
 	"context"
+	"fmt"
 	"testing"
 	"time"
 
@@ -156,6 +157,29 @@ func TestExitWatch(t *testing.T) {
 		time.Sleep(500 * time.Millisecond)
 		server.Close()
 	})
+	// Case6: transfer leader without client reconnection.
+	checkExitWatch(t, leaderKey, func(server *embed.Etcd, client *clientv3.Client) {
+		cfg1 := server.Config()
+		cfg2 := etcdutil.NewTestSingleConfig(t)
+		cfg2.InitialCluster = cfg1.InitialCluster + fmt.Sprintf(",%s=%s", cfg2.Name, &cfg2.LPUrls[0])
+		cfg2.ClusterState = embed.ClusterStateFlagExisting
+		peerURL := cfg2.LPUrls[0].String()
+		addResp, err := etcdutil.AddEtcdMember(client, []string{peerURL})
+		re.NoError(err)
+		etcd2, err := embed.StartEtcd(cfg2)
+		re.NoError(err)
+		re.Equal(uint64(etcd2.Server.ID()), addResp.Member.ID)
+		<-etcd2.Server.ReadyNotify()
+		ep := cfg2.LCUrls[0].String()
+		client1, err := clientv3.New(clientv3.Config{
+			Endpoints: []string{ep},
+		})
+		re.NoError(err)
+
+		server.Server.HardStop()
+		client1.Delete(context.Background(), leaderKey)
+	})
+	// TODO: add test to simulate the case that pd leader is io hang.
 	re.NoError(failpoint.Disable("github.com/tikv/pd/pkg/election/fastTick"))
 	re.NoError(failpoint.Disable("github.com/tikv/pd/pkg/utils/etcdutil/fastTick"))
 }