Illuminate\Http\UploadedFile 提供了一个 fake 方法用于生成虚拟的文件或者图像以供测试之用。它可以和 Storage facade 的 fake 方法相结合，大幅度简化了文件上传测试。举个例子，你可以结合这两者的功能非常方便地进行头像上传表单测试：

<?php

namespace Tests\Feature;

use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithoutMiddleware;
use Illuminate\Http\UploadedFile;
use Illuminate\Support\Facades\Storage;
use Tests\TestCase;

class ExampleTest extends TestCase
{
    public function testAvatarUpload()
    {
        Storage::fake('avatars');

        $file = UploadedFile::fake()->image('avatar.jpg');

        $response = $this->json('POST', '/avatar', [
            'avatar' => $file,
        ]);

        // 断言文件被存储...
        Storage::disk('avatars')->assertExists($file->hashName());

        // 断言文件不存在...
        Storage::disk('avatars')->assertMissing('missing.jpg');
    }
}