Laravel 项目：使用 TDD 构建论坛 Chapter 4

0.写在前面

• 本系列文章为laracasts.com 的系列视频教程——Let's Build A Forum with Laravel and TDD 的学习笔记。若喜欢该系列视频，可去该网站订阅后下载该系列视频， 支持正版 。
• 视频源码地址：https://github.com/laracasts/Lets-Build-a-Forum-in-Laravel
• *本项目为一个 forum（论坛）项目，与本站的第二本实战教程 Laravel 教程 - Web 开发实战进阶 ( Laravel 5.5 ) 类似，可互相参照
• 项目开发模式为TDD开发，教程简介为：

  A forum is a deceptively complex thing. Sure, it's made up of threads and replies, but what else might exist as part of a forum? What about profiles, or thread subscriptions, or filtering, or real-time notifications? As it turns out, a forum is the perfect project to stretch your programming muscles. In this series, we'll work together to build one with tests from A to Z.

• 项目版本为laravel 5.4，教程后面会进行升级到laravel 5.5的教学
• 视频教程共计 102 个小节，笔记章节与视频教程一一对应

1.本节说明

对应视频第 4 小节：A User May Response To Threads

2.本节内容

上节中我们的..\views\threads\show.blade.php视图文件回复区域的内容为：

.
.
<div class="row">
    <div class="col-md-8 col-md-offset-2">
        @ foreach ($thread->replies as $reply) // 此处 @ 后面有空格
            <div class="panel panel-default">
                <div class="panel-heading">
                    {{ $reply->owner->name }} 回复于
                    {{ $reply->created_at->diffForHumans() }}
                </div>

                <div class="panel-body">
                    {{ $reply->body }}
                </div>
            </div>
        @endforeach
    </div>
</div>
.
.

为了便于维护，我们将回复区域抽离成一个单独的视图。修改如下：

.
.
<div class="row">
    <div class="col-md-8 col-md-offset-2">
        @ foreach ($thread->replies as $reply)  // 此处 @ 后面有空格
            @include('threads.reply')
        @endforeach
    </div>
</div>
.
.

新建..\views\threads\reply.blade.php视图文件：

<div class="panel panel-default">
    <div class="panel-heading">
        <a href="#">
            {{ $reply->owner->name }}
        </a>
        回复于 {{ $reply->created_at->diffForHumans() }}
    </div>

    <div class="panel-body">
        {{ $reply->body }}
    </div>
</div>

我们可以给话题的内容加上作者的信息：
..\views\threads\show.blade.php

.
.
<div class="row">
    <div class="col-md-8 col-md-offset-2">
        <div class="panel panel-default">
            <div class="panel-heading">
                <a href="#">{{ $thread->creator->name }}</a> 发表了： 
                {{ $thread->title }}
            </div>

            <div class="panel-body">
                {{ $thread->body }}
            </div>
        </div>
    </div>
</div>
.
.

我们需要先行编写单元测试，用来测试$thread->creator。但是在此之前，由于上一节中我们使用了$thread->replies来获取回复，但并未编写单元测试。现在补上单元测试，首先移除Unit文件夹下的示例文件，并新建单元测试文件：

$ php artisan make:test ThreadTest --unit

修改如下：

<?php

namespace Tests\Unit;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ThreadTest extends TestCase
{
    use DatabaseMigrations;

    /** @test  */
    public function a_thread_has_replies()
    {
        $thread = factory('App\Thread')->create();

        $this->assertInstanceOf('Illuminate\Database\Eloquent\Collection',$thread->replies);
    }
}

测试一下：

$ phpunit tests/Unit/ThreadTest.php

测试通过：

继续编写$thread->creator的测试代码：
ThreadTest.php

.
.
public function test_a_thread_has_a_creator()
{
    $this->assertInstanceOf('App\User',$this->thread->creator);
}
.
.

我们可以使用--filter来单独测试：

$ phpunit --filter a_thread_has_a_creator

因为我们还未进行模型关联：
app\Thread.php

.
.
public function creator()
{
    return $this->belongsTo(User::class,'user_id'); // 使用 user_id 字段进行模型关联
}
.
.

再次测试即可通过，刷新页面即可看到效果：

接下来新建测试：

$ php artisan make:test ParticipateInForumTest

先编写测试逻辑：

<?php

namespace Tests\Feature;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ParticipateInForumTest extends TestCase
{
    use DatabaseMigrations;

    /** @test */
    function an_authenticated_user_may_participate_in_forum_threads()
    {
        // Given we have a authenticated user
        // And an existing thread
        // When the user adds a reply to the thread
        // Then their reply should be visible on the page
    }
}

再填充具体代码：

<?php

namespace Tests\Feature;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ParticipateInForumTest extends TestCase
{
    use DatabaseMigrations;

    function an_authenticated_user_may_participate_in_forum_threads()
    {
        // Given we have a authenticated user
        $this->be($user = factory('App\User')->create());

        // And an existing thread
        $thread = factory('App\Thread')->create();

        // When the user adds a reply to the thread
        $reply = factory('App\Reply')->create();
        $this->post($thread->path().'/replies',$reply->toArray());

        // Then their reply should be visible on the page
        $this->get($thread->path())
            ->assertSee($reply->body);
    }
}

注意到我们使用$thread->path()来获取 URL ，想起在ReadThreadsTest.php文件中可进行优化：
tests\Feature\ReadThreadsTest.php

.
.
/** @test */
public function a_user_can_read_a_single_thread()
{
    $this->get($this->thread->path())  //此处
        ->assertSee($this->thread->title);
}

/** @test */
public function a_user_can_read_replies_that_are_associated_with_a_thread()
{
    // 如果有 Thread
    // 并且该 Thread 有回复
    $reply = factory('App\Reply')
        ->create(['thread_id' => $this->thread->id]);
    // 那么当我们看 Thread 时
    // 我们也要看到回复
    $this->get($this->thread->path())  //还有此处
        ->assertSee($reply->body);

}
.
.

一般而言，当修改已通过的测试时，应该在修改之后（需注释新建的测试）再次测试，确保之前的测试逻辑未被破坏。

$ phpunit

当我们测试新写的测试时：

$ phpunit tests/Feature/ParticipateInForumTest.php

会得到一大段长长的报错信息，要定位到错误十分困难：

在app\Exceptions\Handler.php中加上一行：

.
.
public function render($request, Exception $exception)
{
    if(app()->environment() === 'local') throw $exception;  // 此处加上一行

    return parent::render($request, $exception);
}
.
.

注1：视频教程中使用的是app()->environment() === 'testing'，但经过测试未生效，遂改为以上local。

再次运行测试：

$ phpunit tests/Feature/ParticipateInForumTest.php

现在可以十分容易地定位错误：

添加路由：

Route::post('/threads/{thread}/replies','RepliesController@store');

前往RepliesController增加store方法：

<?php

namespace App\Http\Controllers;

use App\Thread;
use Illuminate\Http\Request;

class RepliesController extends Controller
{
    public function store(Thread $thread)
    {
        $thread->addReply([
            'body' => request('body'),
            'user_id' => auth()->id(),
        ]);
    }
}

为store方法添加单元测试：
ThreadTest.php

<?php

namespace Tests\Unit;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ThreadTest extends TestCase
{
    use DatabaseMigrations;

    protected $thread;

    public function setUp()
    {
        parent::setUp(); // TODO: Change the autogenerated stub

        $this->thread = factory('App\Thread')->create();
    }

    /** @test  */
    public function a_thread_has_replies()
    {

        $this->assertInstanceOf('Illuminate\Database\Eloquent\Collection',$this->thread->replies);
    }

    /** @test */
    public function a_thread_has_a_creator()
    {
        $this->assertInstanceOf('App\User',$this->thread->creator);
    }

    /** @test */
    public function a_thread_can_add_a_reply()
    {
        $this->thread->addReply([
           'body' => 'Foobar',
           'user_id' => 1
        ]);

        $this->assertCount(1,$this->thread->replies);
    }
}

测试一下：

添加addReply方法：
app\Thhread.php

.
.
public function addReply($reply)
{
    $this->replies()->create($reply);
}
.
.

再次运行测试

$ phpunit --filter an_authenticated_user_may_participate_in_forum_threads

结果报错：

按道理说不应该，根据查阅到的资料，在测试环境应该是不会检验CsrfToken。尝试了诸多办法仍旧无法解决，简单用以下方法临时解决：

$ APP_ENV=testing phpunit --filter an_authenticated_user_may_participate_in_forum_threads

即：在运行测试的时候将环境设为testing，未配合使用，应将Hander.php文件中代码改为如下：

.
.
public function render($request, Exception $exception)
{
    if (app()->environment() === 'testing') throw $exception;

    return parent::render($request, $exception);
}
.
.

运行测试：

运行完整测试：

$ APP_ENV=testing phpunit

注1：此处在笔记心得有详细解释。

我们限制只有登录用户才能添加回复，只需利用auth中间件即可：
RepliesController.php

public function __construct()
{
    $this->middleware('auth');
}
.
.

测试如果我们将单元测试代码更改一下：
ParticipateInForumTest.php

<?php

namespace Tests\Feature;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ParticipateInForumTest extends TestCase
{
    use DatabaseMigrations;

    /** @test */
    function an_authenticated_user_may_participate_in_forum_threads()
    {
        // Given we have a authenticated user
//        $this->be($user = factory('App\User')->create()); // 已登录用户
        $user = factory('App\User')->create(); // 未登录用户
        // And an existing thread
        $thread = factory('App\Thread')->create();

        // When the user adds a reply to the thread
        $reply = factory('App\Reply')->create();
        $this->post($thread->path() .'/replies',$reply->toArray()); // 注：此处有修改

        // Then their reply should be visible on the page
        $this->get($thread->path())
            ->assertSee($reply->body);
    }
}

再次运行测试：

$ APP_ENV=testing phpunit

提示用户未认证，说明我们的测试有效。接下来再建立一个测试，测试未登录用户不能添加回复：
ParticipateInForumTest.php

<?php

namespace Tests\Feature;

use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class ParticipateInForumTest extends TestCase
{
    use DatabaseMigrations;

    /** @test */
    public function unauthenticated_user_may_no_add_replies()
    {
        $this->expectException('Illuminate\Auth\AuthenticationException');

        $thread = factory('App\Thread')->create();

        $reply = factory('App\Reply')->create();
        $this->post($thread->path().'/replies',$reply->toArray());
    }

    /** @test */
    function an_authenticated_user_may_participate_in_forum_threads()
    {
        // Given we have a authenticated user
        $this->be($user = factory('App\User')->create());
        // And an existing thread
        $thread = factory('App\Thread')->create();

        // When the user adds a reply to the thread
        $reply = factory('App\Reply')->create();
        $this->post($thread->path() .'/replies',$reply->toArray());

        // Then their reply should be visible on the page
        $this->get($thread->path())
            ->assertSee($reply->body);
    }
}

再次测试：

$ APP_ENV=testing phpunit

成功通过：

实际上，测试未登录用户的代码可以更加简单，因为我们实际上只用测试未登录用户是否抛出异常即可：
ParticipateInForumTest.php

.
.
/** @test */
public function unauthenticated_user_may_no_add_replies()
{
    $this->expectException('Illuminate\Auth\AuthenticationException');

    $this->post('threads/1/replies',[]);
}
.
.

最后，需要修改一下an_authenticated_user_may_participate_in_forum_threads：

.
.
/** @test */
function an_authenticated_user_may_participate_in_forum_threads()
{
    // Given we have a authenticated user
    $this->be($user = factory('App\User')->create());
    // And an existing thread
    $thread = factory('App\Thread')->create();

    // When the user adds a reply to the thread
    $reply = factory('App\Reply')->make();  // -->此处有修改
    $this->post($thread->path() .'/replies',$reply->toArray());

    // Then their reply should be visible on the page
    $this->get($thread->path())
        ->assertSee($reply->body);
}
.
.

注2：详见笔记心得处。

3.笔记心得

• 关于注1的说明：
  第四节课经历比较坎坷，主要是遇到了一个问题：
  

  Illuminate\Session\TokenMismatchException:

  显示的问题应该是CSRF令牌不符，于是定位到
  \vendor\laravel\framework\src\Illuminate\Foundation\Http\Middleware\VerifyCsrfToken.php的tokensMatch方法：

  protected function tokensMatch($request)
  {
  $token = $this->getTokenFromRequest($request);
  
  return is_string($request->session()->token()) &&
         is_string($token) &&
         hash_equals($request->session()->token(), $token);
  }

  发现验证的是$token跟$request->session()->token()的值，于是将两者的值打印出来看看：

  protected function tokensMatch($request)
  {
      $token = $this->getTokenFromRequest($request);
      var_dump($token);
      var_dump($request->session()->token());exit;
      return is_string($request->session()->token()) &&
             is_string($token) &&
             hash_equals($request->session()->token(), $token);
  }

  运行：

  $ phpunit

  
  本以为问题就是因为$token的值是null，然而在看了文章 防范 CSRF 跨站请求伪造-以 Laravel 中间件 VerifyCSRFToken 为例 再结合代码发现，在进行测试时是不需要验证CsrfToken的：
  \vendor\laravel\framework\src\Illuminate\Foundation\Http\Middleware\VerifyCsrfToken.php：

  .
  .
  public function handle($request, Closure $next)
  {
  if (
      $this->isReading($request) ||
      $this->runningUnitTests() ||
      $this->inExceptArray($request) ||
      $this->tokensMatch($request)
  ) {
      return $this->addCookieToResponse($request, $next($request));
  }
  
  throw new TokenMismatchException;
  }
  .
  .

  其中的第二条，$this->runningUnitTests()即意味着在测试时应该放行。于是追溯runningUnitTests方法：

  protected function runningUnitTests()
  {
  return $this->app->runningInConsole() && $this->app->runningUnitTests();
  }

  经过验证，$this->app->runningInConsole()为true。于是接着追溯runningUnitTests方法：

  public function runningUnitTests()
  {
  return $this['env'] == 'testing';
  }

  然后验证到$this['env']的值为local，终于定位到错误：运行测试时的环境为local。令人疑惑的是，phpunit.xml的配置与教程相同，但不知为何没有生效：
  phpunit.xml

  <phpunit backupGlobals="false"
       backupStaticAttributes="false"
       bootstrap="bootstrap/autoload.php"
       colors="true"
       convertErrorsToExceptions="true"
       convertNoticesToExceptions="true"
       convertWarningsToExceptions="true"
       processIsolation="false"
       stopOnFailure="false">
  <testsuites>
      <testsuite name="Feature">
          <directory suffix="Test.php">./tests/Feature</directory>
      </testsuite>
  
      <testsuite name="Unit">
          <directory suffix="Test.php">./tests/Unit</directory>
      </testsuite>
  </testsuites>
  <filter>
      <whitelist processUncoveredFilesFromWhitelist="true">
          <directory suffix=".php">./app</directory>
      </whitelist>
  </filter>
  <php>
      <env name="APP_ENV" value="testing"/>  -->此处将环境设置为 testing，但未生效
      <env name="DB_CONNECTION" value="sqlite"/>
      <env name="DB_DATABASE" value=":memory:"/>
      <env name="CACHE_DRIVER" value="array"/>
      <env name="SESSION_DRIVER" value="array"/>
      <env name="QUEUE_DRIVER" value="sync"/>
  </php>
  </phpunit>

• 关于注2的说明：
  先来看一下create()与make()方法的说明：

  /**
  * Create a collection of models and persist them to the database.
  *
  * @param  array  $attributes
  * @return mixed
  */
  public function create(array $attributes = [])
  {
  $results = $this->make($attributes);
  
  if ($results instanceof Model) {
      $this->store(collect([$results]));
  } else {
      $this->store($results);
  }
  
  return $results;
  }

  /**
  * Create a collection of models.
  *
  * @param  array  $attributes
  * @return mixed
  */
  public function make(array $attributes = [])
  {
  if ($this->amount === null) {
      return $this->makeInstance($attributes);
  }
  
  if ($this->amount < 1) {
      return (new $this->class)->newCollection();
  }
  
  return (new $this->class)->newCollection(array_map(function () use ($attributes) {
      return $this->makeInstance($attributes);
  }, range(1, $this->amount)));
  }

  create()方法会得到一个实例，并将实例保存到数据库中；make()方法只会得到一个实例。在本节的测试中我们不需要保存$thread实例，因为我们会在RepliesController的store()方法进行保存，故使用make()方法。

  另外，create()与make()方法的区别可以参见这篇文章 What does the make() method do in Laravel
  

4.写在后面

• 如有建议或意见，欢迎指出~
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