/**
* @return void
*/
public function testSendMailContainsHeader()
{
$mailTransfer = new MailTransfer();
$mailTransfer->addHeader((new MailHeaderTransfer())->setKey('Header 1')->setValue('Value 1'));
$this->mandrillMock->messages->expects($this->once())->method('sendTemplate')->with($this->anything(), $this->anything(), $this->arrayContainsKeyEqualTo('headers', ['Header 1' => 'Value 1']), $this->anything(), $this->anything(), $this->anything());
$this->mailSender->sendMail($mailTransfer);
}
