public function testToWebFormatWithFilters()
{
$email = new \SendGrid\Email();
$email->addFilter('footer', 'text/plain', 'Here is a plain text footer');
$json = $email->toWebFormat();
$xsmtpapi = json_decode($json['x-smtpapi'], TRUE);
$this->assertEquals('Here is a plain text footer', $xsmtpapi['filters']['footer']['settings']['text/plain']);
}