truncate should not change offset

improved Fsetstat test case

client.go

@@ -1301,15 +1301,7 @@ func (f *File) Chmod(mode os.FileMode) error {
 // size greater than the current size.
 // We send a SSH_FXP_FSETSTAT here since we have a file handle
 func (f *File) Truncate(size int64) error {
-	err := f.c.setfstat(f.handle, sshFileXferAttrSize, uint64(size))
-	if err == nil {
-		// reset the offset for future writes
-		f.mu.Lock()
-		defer f.mu.Unlock()
-
-		f.offset = uint64(size)
-	}
-	return err
+	return f.c.setfstat(f.handle, sshFileXferAttrSize, uint64(size))
 }
 
 func min(a, b int) int {

request-server_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 var _ = fmt.Print
@@ -349,31 +350,29 @@ func TestRequestFsetstat(t *testing.T) {
 	p := clientRequestServerPair(t)
 	defer p.Close()
 	_, err := putTestFile(p.cli, "/foo", "hello")
-	assert.Nil(t, err)
+	require.NoError(t, err)
 	fp, err := p.cli.OpenFile("/foo", os.O_WRONLY)
-	assert.Nil(t, err)
+	require.NoError(t, err)
 	err = fp.Truncate(2)
+	require.NoError(t, err)
+	fi, err := fp.Stat()
 	if assert.NoError(t, err) {
-		fi, err := fp.Stat()
-		if assert.NoError(t, err) {
-			assert.Equal(t, fi.Name(), "foo")
-			assert.Equal(t, fi.Size(), int64(2))
-		}
+		assert.Equal(t, fi.Name(), "foo")
+		assert.Equal(t, fi.Size(), int64(2))
 	}
-	// we expect the truncate size (2) as offset for this write
+	_, err = fp.Seek(int64(2), io.SeekStart)
+	assert.NoError(t, err)
 	n, err := fp.Write([]byte("hello"))
 	assert.NoError(t, err)
 	assert.Equal(t, 5, n)
 	err = fp.Close()
 	assert.NoError(t, err)
 	rf, err := p.cli.Open("/foo")
-	assert.Nil(t, err)
+	assert.NoError(t, err)
 	defer rf.Close()
 	contents := make([]byte, 20)
 	n, err = rf.Read(contents)
-	if err != nil && err != io.EOF {
-		t.Fatalf("err: %v", err)
-	}
+	assert.EqualError(t, err, io.EOF.Error())
 	assert.Equal(t, 2+5, n)
 	assert.Equal(t, "hehello", string(contents[0:n]))
 	checkRequestServerAllocator(t, p)