Merge pull request etcd-io#17235 from fuweid/fix-17223

integration: deflake TestMaintenanceSnapshotCancel

tests/integration/clientv3/maintenance_test.go

@@ -26,6 +26,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap/zaptest"
 	"google.golang.org/grpc"
@@ -176,6 +177,12 @@ func TestMaintenanceSnapshotCancel(t *testing.T) {
 	}
 	defer rc1.Close()
 
+	// read 16 bytes to ensure that server opens snapshot
+	buf := make([]byte, 16)
+	n, err := rc1.Read(buf)
+	assert.NoError(t, err)
+	assert.Equal(t, 16, n)
+
 	cancel()
 	_, err = io.Copy(io.Discard, rc1)
 	if err != context.Canceled {