Route::post('register', function () {
    // <snip> Validation, create account, etc. </snip>

    Mail::send('emails.welcome', [], function ($m) {
        $email = request('email');
        $m->to($email);
        $m->subject('Welcome to my app!');
        $m->from('[email protected]');
        $m->bcc('[email protected]');
    });

    // <snip> Return response </snip>
});

use MailThief\Facades\MailThief;

class RegistrationTest extends TestCase
{
    public function test_new_users_are_sent_a_welcome_email()
    {
        // Block and intercept outgoing mail, important!
        MailThief::hijack();

        $this->post('register', [
            'name' => 'John Doe',
            'email' => '[email protected]',
            'password' => 'secret',
        ]);

        // Check that an email was sent to this email address
        $this->assertTrue(MailThief::hasMessageFor('[email protected]'));

        // BCC addresses are included too
        $this->assertTrue(MailThief::hasMessageFor('[email protected]'));

        // Make sure the email has the correct subject
        $this->assertEquals('Welcome to my app!', MailThief::lastMessage()->subject);

        // Make sure the email was sent from the correct address
        // (`from` can be a list, so we return it as a collection)
        $this->assertEquals('[email protected]', MailThief::lastMessage()->from->first());
    }
}