Using non-default mailers

[ejunker]

I have multiple mailers configured in my config/mail.php with the default set to sendmail

    'default' => env('MAIL_MAILER', 'sendmail'),

    'mailers' => [
        'sendmail' => [
            'transport' => 'sendmail',
            'path' => env('MAIL_SENDMAIL_PATH', '/usr/sbin/sendmail -bs -i'),
        ],

        'sparkpost' => [
            'transport' => 'sparkpost',
        ],

If I have code that uses a specific mailer to send mail I do something like this in my test:

class MailableTest extends TestCase
{
    use WithMailInterceptor;

    public function test_example(): void
    {
        $this->interceptMail();
        Mail::mailer('sparkpost')->send(new MyMailable());
        $this->assertNotEmpty($this->interceptedMail());
    }
}

This test fails. I discovered if I change:

    public function interceptedMail(): Collection
    {
        return app('mailer')->getSymfonyTransport()
            ->messages()
            ->map(function (SentMessage $message) {
                return new AssertableMessage($message->getOriginalMessage());
            });
    }

to using the mail manager and allow specifying the mailer like this:

    public function interceptedMail(?string $mailer = null): Collection
    {
        return app('mail.manager')->mailer($mailer)->getSymfonyTransport()
            ->messages()
            ->map(function (SentMessage $message) {
                return new AssertableMessage($message->getOriginalMessage());
            });
    }

and then in my test do this it works:

$this->assertNotEmpty($this->interceptedMail('sparkpost'));

Is there a better way to handle this? This was just an example test; in the real world this would be a feature test where I am not sending the mailable directly in the test but rather making a request to my app that generates the email.

I was considering creating a PR with this change, but I wasn't sure how to add a test that covers this functionality.