address comment

pkg/task/backup.go

@@ -50,7 +50,8 @@ func DefineBackupFlags(flags *pflag.FlagSet) {
 		"The history version of the backup task, e.g. 1m, 1h. Do not exceed GCSafePoint")
 
 	// TODO: remove experimental tag if it's stable
-	flags.Uint64(flagLastBackupTS, 0, "(experimental) the last time backup ts, use for incremental backup, support TSO only")
+	flags.Uint64(flagLastBackupTS, 0, "(experimental) the last time backup ts,"+
+		" use for incremental backup, support TSO only")
 	flags.String(flagBackupTS, "", "the backup ts support TSO or datetime,"+
 		" e.g. '400036290571534337', '2018-05-11 01:42:23' ")
 }

pkg/task/backup_test.go

@@ -2,6 +2,7 @@ package task
 
 import (
 	"testing"
+	"time"
 
 	. "github.com/pingcap/check"
 )
@@ -28,7 +29,9 @@ func (s *testBackupSuite) TestParseTSString(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(int(ts), Equals, 400036290571534337)
 
+	utcTS := 400024965742563200
+	_, offset := time.Now().Local().Zone()
 	ts, err = parseTSString("2018-05-11 01:42:23")
 	c.Assert(err, IsNil)
-	c.Assert(int(ts), Equals, 400024965742592000)
+	c.Assert(int(ts), Equals, utcTS+offset)
 }