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: obfuscated2_test.go
    path of file: ./repos/td/mtproxy/obfuscated2
    
    the code of the file until where you have to start completion: package obfuscated2

import (
	"bytes"
	"encoding/hex"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"
)

type OneChar struct {
	char byte
}

func (c OneChar) Read(p []byte) (n int, err error) {
	for i := range p {
		p[i] = c.char
	}
	return len(p), nil
}

func Test_generateKeys(t *testing.T) {
	a := require.New(t)
	secret, err := hex.DecodeString(strings.Repeat("a", 32))
	a.NoError(err)

	k, err := generateKeys(OneChar{char: 'a'}, [4]byte{0xdd, 0xdd, 0xdd, 0xdd}, secret, 2)
	a.NoError(err)

	var expectedHeader = []byte{
		97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97,
		97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97,
		97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97,
		97, 97, 97, 97, 97, 171, 65, 98, 66, 79, 102, 253, 220,
	}
	a.Equal(expectedHeader, k.header)
}

func TestEncrypt(t *testing.T) {
	a := require.New
    
func TestEncrypt(t *testing.T) {
	a := require.New(t)
	secret, err := hex.DecodeString("8a96ef6e42a18c21837580cd1c91c5a8")
	a.NoError(err)

	rand := []byte{
		245, 118, 143, 80, 183, 49, 38, 10, 70, 190, 16, 39, 194, 238, 170,
		57, 53, 6, 36, 240, 182, 218, 89, 235, 165, 108, 129, 254, 69, 16,
		194, 224, 182, 29, 61, 211, 35, 238, 2, 56, 134, 51, 227, 131, 122,
		12, 28, 36, 250, 111, 41, 204, 215, 36, 190, 111, 65, 111, 247, 176,
		38, 246, 204, 230,
	}
	k, err := generateKeys(bytes.NewReader(rand), [4]byte{0xdd, 0xdd, 0xdd, 0xdd}, secret, 2)
	a.NoError(err)

	var expectedHeader = []byte{
		245, 118, 143, 80, 183, 49, 38, 10, 70, 190, 16, 39, 194, 238, 170, 57, 53, 6, 36, 240,
		182, 218, 89, 235, 165, 108, 129, 254, 69, 16, 194, 224, 182, 29, 61, 211, 35, 238,
		2, 56, 134, 51, 227, 131, 122, 12, 28, 36, 250, 111, 41, 204, 215, 36, 190, 111,
		190, 162, 221, 225, 109, 197, 157, 210,
	}
	a.Equal(expectedHeader, k.header)

	var encrypted [4]byte
	payload := []byte{'a', 'b', 'c', 'd'}
	k.encrypt.XORKeyStream(encrypted[:], payload)
	a.Equal([]byte{202, 122, 130, 38}, encrypted[:])

	k.decrypt.XORKeyStream(encrypted[:], payload)
	a.Equal([]byte{143, 113, 25, 130}, encrypted[:])
}