fix test suite race

Signed-off-by: Ryan Leung <rleungx@gmail.com>

tests/cluster.go

@@ -46,6 +46,7 @@ import (
 	"github.com/tikv/pd/server/config"
 	"github.com/tikv/pd/server/join"
 	"go.etcd.io/etcd/clientv3"
+	"go.uber.org/atomic"
 )
 
 // TestServer states.
@@ -70,7 +71,7 @@ type TestServer struct {
 	sync.RWMutex
 	server     *server.Server
 	grpcServer *server.GrpcServer
-	state      int32
+	state      atomic.Int32
 }
 
 var zapLogOnce sync.Once
@@ -106,47 +107,49 @@ func createTestServer(ctx context.Context, cfg *config.Config, services []string
 	return &TestServer{
 		server:     svr,
 		grpcServer: &server.GrpcServer{Server: svr},
-		state:      Initial,
+		state:      *atomic.NewInt32(Initial),
 	}, nil
 }
 
 // Run starts to run a TestServer.
 func (s *TestServer) Run() error {
 	s.Lock()
 	defer s.Unlock()
-	if s.state != Initial && s.state != Stop {
-		return errors.Errorf("server(state%d) cannot run", s.state)
+	state := s.state.Load()
+	if state != Initial && state != Stop {
+		return errors.Errorf("server(state%d) cannot run", state)
 	}
 	if err := s.server.Run(); err != nil {
 		return err
 	}
-	s.state = Running
+	s.state.Store(Running)
 	return nil
 }
 
 // Stop is used to stop a TestServer.
 func (s *TestServer) Stop() error {
 	s.Lock()
 	defer s.Unlock()
-	if s.state != Running {
-		return errors.Errorf("server(state%d) cannot stop", s.state)
+	state := s.state.Load()
+	if state != Running {
+		return errors.Errorf("server(state%d) cannot stop", state)
 	}
 	s.server.Close()
-	s.state = Stop
+	s.state.Store(Stop)
 	return nil
 }
 
 // Destroy is used to destroy a TestServer.
 func (s *TestServer) Destroy() error {
 	s.Lock()
 	defer s.Unlock()
-	if s.state == Running {
+	if s.state.Load() == Running {
 		s.server.Close()
 	}
 	if err := os.RemoveAll(s.server.GetConfig().DataDir); err != nil {
 		return err
 	}
-	s.state = Destroy
+	s.state.Store(Destroy)
 	return nil
 }
 
@@ -162,7 +165,7 @@ func (s *TestServer) ResignLeader() error {
 func (s *TestServer) State() int32 {
 	s.RLock()
 	defer s.RUnlock()
-	return s.state
+	return s.state.Load()
 }
 
 // GetConfig returns the current TestServer's configuration.
@@ -628,7 +631,7 @@ func (c *TestCluster) WaitLeader(ops ...WaitOption) string {
 		counter := make(map[string]int)
 		running := 0
 		for _, s := range c.servers {
-			if s.state == Running {
+			if s.state.Load() == Running {
 				running++
 			}
 			n := s.GetLeader().GetName()
@@ -695,7 +698,7 @@ func (c *TestCluster) WaitAllocatorLeader(dcLocation string, ops ...WaitOption)
 		counter := make(map[string]int)
 		running := 0
 		for _, s := range c.servers {
-			if s.state == Running && s.GetTSOAllocatorManager().EnableLocalTSO() {
+			if s.state.Load() == Running && s.GetTSOAllocatorManager().EnableLocalTSO() {
 				running++
 			}
 			serverName := s.GetAllocatorLeader(dcLocation).GetName()