/**
  * @expectedException HttpSignatures\SignatureParseException
  */
 public function testParseExceptionForMissingComponents()
 {
     $parser = new SignatureParametersParser('keyId="example",algorithm="hmac-sha1",headers="(request-target) date"');
     $parser->parse();
 }
 /**
  * @return array
  *
  * @throws Exception
  */
 private function parameters()
 {
     if (!isset($this->_parameters)) {
         $parser = new SignatureParametersParser($this->signatureHeader());
         $this->_parameters = $parser->parse();
     }
     return $this->_parameters;
 }