Issue 305 client write

client.go

@@ -167,6 +167,10 @@ type Client struct {
 // already exists. If successful, methods on the returned File can be used for
 // I/O; the associated file descriptor has mode O_RDWR. If you need more
 // control over the flags/mode used to open the file see client.OpenFile.
+//
+// Note that some SFTP servers (eg. AWS Transfer) do not support opening files
+// read/write at the same time. For those services you will need to use
+// `client.OpenFile(os.O_WRONLY|os.O_CREATE|os.O_TRUNC)`.
 func (c *Client) Create(path string) (*File, error) {
 	return c.open(path, flags(os.O_RDWR|os.O_CREATE|os.O_TRUNC))
 }

sftp.go

@@ -219,4 +219,11 @@ type StatusError struct {
 	msg, lang string
 }
 
-func (s *StatusError) Error() string { return fmt.Sprintf("sftp: %q (%v)", s.msg, fx(s.Code)) }
+func (s *StatusError) Error() string {
+	return fmt.Sprintf("sftp: %q (%v)", s.msg, fx(s.Code))
+}
+
+// FxCode returns the error code typed to match against the exported codes
+func (s *StatusError) FxCode() fxerr {
+	return fxerr(s.Code)
+}

sftp_test.go

@@ -0,0 +1,28 @@
+package sftp
+
+import (
+	"io"
+	"syscall"
+	"testing"
+
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestErrFxCode(t *testing.T) {
+	ider := sshFxpStatusPacket{ID: 1}
+	table := []struct {
+		err error
+		fx  fxerr
+	}{
+		{err: errors.New("random error"), fx: ErrSSHFxFailure},
+		{err: syscall.EBADF, fx: ErrSSHFxFailure},
+		{err: syscall.ENOENT, fx: ErrSSHFxNoSuchFile},
+		{err: syscall.EPERM, fx: ErrSSHFxPermissionDenied},
+		{err: io.EOF, fx: ErrSSHFxEOF},
+	}
+	for _, tt := range table {
+		statusErr := statusFromError(ider, tt.err).StatusError
+		assert.Equal(t, statusErr.FxCode(), tt.fx)
+	}
+}