warning when trying to load empty string as public key #2079
Description
loadXML documents that it will send a warning if it tries to read an empty string. This came up when I was writing unit tests for garbage public keys, because phpunit is configured to convert warnings to errors.
ValueError: DOMDocument::loadXML(): Argument #1 ($source) must not be empty
.../phpseclib/Crypt/EC/Formats/Keys/XML.php:142
.../phpseclib/Crypt/EC/Formats/Keys/XML.php:77
.../phpseclib/Crypt/Common/AsymmetricKey.php:145
.../phpseclib/Crypt/PublicKeyLoader.php:40