When I updated from version 1.9.7 to version 1.9.8 my AuthorizeNet unit tests started failing. After tracing the code I found the problem to be with the fact that some classes were now deprecated and in the /deprecated/shared folder. The AuthorizeNetRequest.php class has the following line:

curl_setopt($curl_request, CURLOPT_CAINFO, dirname(dirname(__FILE__)) . '/ssl/cert.pem');

but reference to the /ssl folder causes curl_execute to throw an exception because the /ssl folder does not exist in the new /deprecated folder. Moving the /ssl folder to the /deprecated folder solved the problem and allowed the tests to complete successfully.