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: prepared_test.go
    path of file: ./repos/websocket
    
    the code of the file until where you have to start completion: // Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package websocket

import (
	"bytes"
	"compress/flate"
	"math/rand"
	"testing"
)

var preparedMessageTests = []struct {
	messageType            int
	isServer               bool
	enableWriteCompression bool
	compressionLevel       int
}{
	// Server
	{TextMessage, true, false, flate.BestSpeed},
	{TextMessage, true, true, flate.BestSpeed},
	{TextMessage, true, true, flate.BestCompression},
	{PingMessage, true, false, flate.BestSpeed},
	{PingMessage, true, true, flate.BestSpeed},

	// Client
	{TextMessage, false, false, flate.BestSpeed},
	{TextMessage, false, true, flate.BestSpeed},
	{TextMessage, false, true, flate.BestCompression},
	{PingMessage, false, false, flate.BestSpeed},
	{PingMessage, false, true, flate.BestSpeed},
}

func TestPreparedMessage(t *testing.T) {
	t
    
func TestPreparedMessage(t *testing.T) {
	testRand := rand.New(rand.NewSource(99))
	prevMaskRand := maskRand
	maskRand = testRand
	defer func() { maskRand = prevMaskRand }()

	for _, tt := range preparedMessageTests {
		var data = []byte("this is a test")
		var buf bytes.Buffer
		c := newTestConn(nil, &buf, tt.isServer)
		if tt.enableWriteCompression {
			c.newCompressionWriter = compressNoContextTakeover
		}

		if err := c.SetCompressionLevel(tt.compressionLevel); err != nil {
			t.Fatal(err)
		}

		// Seed random number generator for consistent frame mask.
		testRand.Seed(1234)

		if err := c.WriteMessage(tt.messageType, data); err != nil {
			t.Fatal(err)
		}
		want := buf.String()

		pm, err := NewPreparedMessage(tt.messageType, data)
		if err != nil {
			t.Fatal(err)
		}

		// Scribble on data to ensure that NewPreparedMessage takes a snapshot.
		copy(data, "hello world")

		// Seed random number generator for consistent frame mask.
		testRand.Seed(1234)

		buf.Reset()
		if err := c.WritePreparedMessage(pm); err != nil {
			t.Fatal(err)
		}
		got := buf.String()

		if got != want {
			t.Errorf("write message != prepared message, got %#v, want %#v", got, want)
		}
	}
}