Patterns don't start with '/' according to the mailing list

Author: fidian

src/Json/Validator.php

@@ -500,7 +500,7 @@ protected function checkExclusiveMaximum($entity, $schema, $entityName)
     protected function checkPattern($entity, $schema, $entityName)
     {
         if (isset($schema->pattern) && $schema->pattern) {
-            if (!preg_match($schema->pattern, $entity)) {
+            if (!preg_match('/' . $schema->pattern . '/', $entity)) {
                 throw new ValidationException(sprintf('String does not match pattern for [%s]', $entityName));
             }
         }
@@ -756,4 +756,4 @@ protected function checkDivisibleBy($entity, $schema, $entityName)
 
         return $this;
     }
-}
+}

tests/mock/pattern.json

@@ -1,4 +1,4 @@
 {
     "type" : "string",
-    "pattern" : "/^[A-Z]+$/"
-}
+    "pattern" : "^[A-Z]+$"
+}