getMultipleRecords example

    public function testHandleBatch()
    {
        $handler = new MailerHandler($this->mailer, (new Email())->subject('Alert: %level_name% %message%'));
        $handler->setFormatter(new LineFormatter());
        $this->mailer
            ->expects($this->once())
            ->method('send')
            ->with($this->callback(fn (Email $email) => 'Alert: ERROR error' === $email->getSubject() && null === $email->getHtmlBody()))
        ;
        $handler->handleBatch($this->getMultipleRecords());
    }

    public function testMessageCreationIsLazyWhenUsingCallback()
    {
        $this->mailer
            ->expects($this->never())
            ->method('send')
        ;

        $callback = function D) {
            throw new \RuntimeException('Email creation callback should not have been called in this test');
        };