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: smtp_test.go
    path of file: ./repos/gccrs/libgo/go/net/smtp
    
    the code of the file until where you have to start completion: // Copyright 2010 The Go 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 smtp

import (
	"bufio"
	"bytes"
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"internal/testenv"
	"io"
	"net"
	"net/textproto"
	"runtime"
	"strings"
	"testing"
	"time"
)

type authTest struct {
	auth       Auth
	challenges []string
	name       string
	responses  []string
}

var authTests = []authTest{
	{PlainAuth("", "user", "pass", "testserver"), []string{}, "PLAIN", []string{"\x00user\x00pass"}},
	{PlainAuth("foo", "bar", "baz", "testserver"), []string{}, "PLAIN", []string{"foo\x00bar\x00baz"}},
	{CRAMMD5Auth("user", "pass"), []string{"<123456.1322876914@testserver>"}, "CRAM-MD5", []string{"", "user 287eb355114cf5c471c26a875f1ca4ae"}},
}

func TestAuth(t *testing.T) {
testLoop:
	for i, test := range authTests {

    
func TestHello(t *testing.T) {

	if len(helloServer) != len(helloClient) {
		t.Fatalf("Hello server and client size mismatch")
	}

	for i := 0; i < len(helloServer); i++ {
		server := strings.Join(strings.Split(baseHelloServer+helloServer[i], "\n"), "\r\n")
		client := strings.Join(strings.Split(baseHelloClient+helloClient[i], "\n"), "\r\n")
		var cmdbuf bytes.Buffer
		bcmdbuf := bufio.NewWriter(&cmdbuf)
		var fake faker
		fake.ReadWriter = bufio.NewReadWriter(bufio.NewReader(strings.NewReader(server)), bcmdbuf)
		c, err := NewClient(fake, "fake.host")
		if err != nil {
			t.Fatalf("NewClient: %v", err)
		}
		defer c.Close()
		c.localName = "customhost"
		err = nil

		switch i {
		case 0:
			err = c.Hello("hostinjection>\n\rDATA\r\nInjected message body\r\n.\r\nQUIT\r\n")
			if err == nil {
				t.Errorf("Expected Hello to be rejected due to a message injection attempt")
			}
			err = c.Hello("customhost")
		case 1:
			err = c.StartTLS(nil)
			if err.Error() == "502 Not implemented" {
				err = nil
			}
		case 2:
			err = c.Verify("test@example.com")
		case 3:
			c.tls = true
			c.serverName = "smtp.google.com"
			err = c.Auth(PlainAuth("", "user", "pass", "smtp.google.com"))
		case 4:
			err = c.Mail("test@example.com")
		case 5:
			ok, _ := c.Extension("feature")
			if ok {
				t.Errorf("Expected FEATURE not to be supported")
			}
		case 6:
			err = c.Reset()
		case 7:
			err = c.Quit()
		case 8:
			err = c.Verify("test@example.com")
			if err != nil {
				err = c.Hello("customhost")
				if err != nil {
					t.Errorf("Want error, got none")
				}
			}
		case 9:
			err = c.Noop()
		default:
			t.Fatalf("Unhandled command")
		}

		if err != nil {
			t.Errorf("Command %d failed: %v", i, err)
		}

		bcmdbuf.Flush()
		actualcmds := cmdbuf.String()
		if client != actualcmds {
			t.Errorf("Got:\n%s\nExpected:\n%s", actualcmds, client)
		}
	}
}