test/app/Mail/Demo.php

<?php

namespace App\Mail;

use Illuminate\Bus\Queueable;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Contracts\Queue\ShouldQueue;

class Demo extends Mailable
{
    use Queueable, SerializesModels;

    protected $data;

    public function __construct(array $data)
    {
        $this->data = $data;
    }

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->from('email@email.yinqingli.com.cn')->view('emails/demo')->with($this->data);
    }
}