Fix error key conventions (simplesamlphp#2510)

Author: ioigoume

modules/saml/src/Message.php

@@ -195,10 +195,10 @@ public static function checkSign(Configuration $srcMetadata, SignedElement $elem
                 $lastException = new SSP_Error\Error(
                     [
                         ErrorCodes::NOTVALIDCERTSIGNATURE,
-                        'message' => (new ErrorCodes())->getMessage(ErrorCodes::NOTVALIDCERTSIGNATURE),
-                        'element' => get_class($element),
-                        'issuer' => $element->getIssuer()->getValue(),
-                        'entityid' => $srcMetadata->getString('entityid'),
+                        '%MESSAGE%' => (new ErrorCodes())->getMessage(ErrorCodes::NOTVALIDCERTSIGNATURE),
+                        '%ELEMENT%' => get_class($element),
+                        '%ISSUER%' => $element->getIssuer()->getValue(),
+                        '%ENTITYID%' => $srcMetadata->getString('entityid'),
                     ],
                     $e->getPrevious(),
                 );

tests/modules/saml/MessageTest.php

@@ -199,10 +199,10 @@ public function testCheckSignThrowsWhenCertificateMismatch(): void
         $this->expectException(SSP_Error\Error::class);
         $expectedMessage =  [
             'errorCode' => ErrorCodes::NOTVALIDCERTSIGNATURE,
-            'message' => (new ErrorCodes())->getMessage(ErrorCodes::NOTVALIDCERTSIGNATURE),
-            'element'  => 'SAML2\AuthnRequest',
-            'issuer'   => 'https://sp.acmee.com/demo',
-            'entityid' => 'https://idp.acmee.com/example',
+            '%MESSAGE%' => (new ErrorCodes())->getMessage(ErrorCodes::NOTVALIDCERTSIGNATURE),
+            '%ELEMENT%'  => 'SAML2\AuthnRequest',
+            '%ISSUER%'   => 'https://sp.acmee.com/demo',
+            '%ENTITYID%' => 'https://idp.acmee.com/example',
         ];
 
         $this->expectExceptionMessage(json_encode($expectedMessage));