You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: saltpack_test.go
    path of file: ./repos/client/go/libkb
    
    the code of the file until where you have to start completion: // Copyright 2015 Keybase, Inc. All rights reserved. Use of
// this source code is governed by the included BSD license.

package libkb

import (
	"bytes"
	"strings"
	"testing"

	"github.com/keybase/saltpack"
	saltpackBasic "github.com/keybase/saltpack/basic"
	"github.com/stretchr/testify/require"

	"github.com/keybase/client/go/saltpackkeystest"
)

type outputBuffer struct {
	bytes.Buffer
}

func (ob outputBuffer) Close() error {
	return nil
}

// Encrypt a message, and make sure recipients can decode it, and
// non-recipients can't decode it.
func TestSaltpackEncDec(t *testing.T) {
	tc := SetupTest(t, "TestSaltpackEncDec", 1)
	defer tc.Cleanup()

	m := NewMetaContextForTest(tc)

	senderKP, err := GenerateNaclDHKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	senderSigningKP, err := GenerateNaclSigningKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	var receiverKPs []NaclDHKeyPair
	var receiverPKs []NaclDHKeyPublic
	for i := 0; i < 12; i++ {
		kp, err := GenerateNaclDHKeyPair()
		if err != nil {
			t.Fatal(err)
		}
		receiverKPs = append(receiverKPs, kp)
		receiverPKs = append(receiverPKs, kp.Public)
	}

	nonReceiverKP, err := GenerateNaclDHKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	message := "The Magic Words are Squeamish Ossifrage"

	var buf outputBuffer

	arg := SaltpackEncryptArg{
		Source:        strings.NewReader(message),
		Sink:          &buf,
		Receivers:     receiverPKs,
		Sender:      
    
func TestSaltpackEncDec(t *testing.T) {
	tc := SetupTest(t, "TestSaltpackEncDec", 1)
	defer tc.Cleanup()

	m := NewMetaContextForTest(tc)

	senderKP, err := GenerateNaclDHKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	senderSigningKP, err := GenerateNaclSigningKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	var receiverKPs []NaclDHKeyPair
	var receiverPKs []NaclDHKeyPublic
	for i := 0; i < 12; i++ {
		kp, err := GenerateNaclDHKeyPair()
		if err != nil {
			t.Fatal(err)
		}
		receiverKPs = append(receiverKPs, kp)
		receiverPKs = append(receiverPKs, kp.Public)
	}

	nonReceiverKP, err := GenerateNaclDHKeyPair()
	if err != nil {
		t.Fatal(err)
	}

	message := "The Magic Words are Squeamish Ossifrage"

	var buf outputBuffer

	arg := SaltpackEncryptArg{
		Source:        strings.NewReader(message),
		Sink:          &buf,
		Receivers:     receiverPKs,
		Sender:        senderKP,
		SenderSigning: senderSigningKP,
	}
	if err := SaltpackEncrypt(m, &arg); err != nil {
		t.Fatal(err)
	}

	ciphertext := buf.String()
	if !strings.HasPrefix(ciphertext, saltpack.MakeArmorHeader(saltpack.MessageTypeEncryption, KeybaseSaltpackBrand)) {
		t.Errorf("ciphertext doesn't have header: %s", ciphertext)
	}

	if !strings.HasSuffix(ciphertext, saltpack.MakeArmorFooter(saltpack.MessageTypeEncryption, KeybaseSaltpackBrand)+".\n") {
		t.Errorf("ciphertext doesn't have footer: %s", ciphertext)
	}

	for _, key := range receiverKPs {
		buf.Reset()

		// Create a keyring with only one key
		keyring := saltpackBasic.NewKeyring()
		keyring.ImportBoxKey((*[NaclDHKeysize]byte)(&key.Public), (*[NaclDHKeysize]byte)(key.Private))

		_, err = SaltpackDecrypt(m,
			strings.NewReader(ciphertext),
			&buf, keyring, nil, nil, saltpackkeystest.NewMockPseudonymResolver(t))
		if err != nil {
			t.Fatal(err)
		}

		plaintext := buf.String()
		if plaintext != message {
			t.Errorf("expected %s, got %s",
				message, plaintext)
		}
	}

	// Sender is a non-recipient, too.
	nonReceiverKPs := []NaclDHKeyPair{nonReceiverKP, senderKP}

	for _, key := range nonReceiverKPs {
		buf.Reset()

		// Create a keyring with only one key
		keyring := saltpackBasic.NewKeyring()
		keyring.ImportBoxKey((*[NaclDHKeysize]byte)(&key.Public), (*[NaclDHKeysize]byte)(key.Private))

		_, err = SaltpackDecrypt(m,
			strings.NewReader(ciphertext), &buf, keyring, nil, nil, saltpackkeystest.NewMockPseudonymResolver(t))
		// An unauthorized receiver trying to decrypt should receive an error
		decError := err.(DecryptionError)
		require.Equal(t, decError.Cause.Err, saltpack.ErrNoDecryptionKey)
	}
}