pass error code as a string

Author: xabbuh

Tests/Validator/AbstractTest.php

@@ -511,7 +511,7 @@ public function testAddCustomizedViolation()
                 ->setParameter('%param%', 'value')
                 ->setInvalidValue('Invalid value')
                 ->setPlural(2)
-                ->setCode(42)
+                ->setCode('42')
                 ->addViolation();
         };
 
@@ -528,7 +528,7 @@ public function testAddCustomizedViolation()
         $this->assertSame($entity, $violations[0]->getRoot());
         $this->assertSame('Invalid value', $violations[0]->getInvalidValue());
         $this->assertSame(2, $violations[0]->getPlural());
-        $this->assertSame(42, $violations[0]->getCode());
+        $this->assertSame('42', $violations[0]->getCode());
     }
 
     public function testNoDuplicateValidationIfClassConstraintInMultipleGroups()