DebTik/internal/cli/telnet_test.go

package cli

import (
	"bytes"
	"io"
	"net"
	"testing"
	"time"
)

type fragmentConn struct {
	chunks  [][]byte
	written bytes.Buffer
}

func (c *fragmentConn) Read(p []byte) (int, error) {
	if len(c.chunks) == 0 {
		return 0, io.EOF
	}
	b := c.chunks[0]
	n := copy(p, b)
	if n == len(b) {
		c.chunks = c.chunks[1:]
	} else {
		c.chunks[0] = b[n:]
	}
	return n, nil
}
func (c *fragmentConn) Write(p []byte) (int, error)      { return c.written.Write(p) }
func (c *fragmentConn) Close() error                     { return nil }
func (c *fragmentConn) LocalAddr() net.Addr              { return nil }
func (c *fragmentConn) RemoteAddr() net.Addr             { return nil }
func (c *fragmentConn) SetDeadline(time.Time) error      { return nil }
func (c *fragmentConn) SetReadDeadline(time.Time) error  { return nil }
func (c *fragmentConn) SetWriteDeadline(time.Time) error { return nil }
func TestTelnetFragmentedNegotiationAndNewline(t *testing.T) {
	c := &fragmentConn{chunks: [][]byte{{'a', iac}, {do}, {optEcho, '\r'}, {'\n', 'b'}}}
	tc := NewTelnetConn(c)
	got, err := io.ReadAll(tc)
	if err != nil || string(got) != "a\nb" {
		t.Fatalf("got %q, %v", got, err)
	}
	if !bytes.Contains(c.written.Bytes(), []byte{iac, will, optEcho}) {
		t.Fatal("missing option response")
	}
	n, err := tc.Write([]byte("a\nb"))
	if err != nil || n != 3 {
		t.Fatalf("write %d %v", n, err)
	}
}