[Validator] Fix support of Enum to ConstraintValidator::formatValue

Author: PhoneixS

ConstraintValidator.php

@@ -99,6 +99,10 @@ protected function formatValue($value, int $format = 0)
             return $value->format('Y-m-d H:i:s');
         }
 
+        if ($value instanceof \UnitEnum) {
+            return $value->name;
+        }
+
         if (\is_object($value)) {
             if (($format & self::OBJECT_TO_STRING) && method_exists($value, '__toString')) {
                 return $value->__toString();

Tests/ConstraintValidatorTest.php

@@ -41,6 +41,7 @@ public static function formatValueProvider()
             ['array', []],
             ['object', $toString = new TestToStringObject()],
             ['ccc', $toString, ConstraintValidator::OBJECT_TO_STRING],
+            ['FirstCase', $toString = TestEnum::FirstCase],
             ['object', $dateTime = new \DateTimeImmutable('1971-02-02T08:00:00UTC')],
             [class_exists(\IntlDateFormatter::class) ? 'Oct 4, 2019, 11:02 AM' : '2019-10-04 11:02:03', new \DateTimeImmutable('2019-10-04T11:02:03+09:00'), ConstraintValidator::PRETTY_DATE],
             [class_exists(\IntlDateFormatter::class) ? 'Feb 2, 1971, 8:00 AM' : '1971-02-02 08:00:00', $dateTime, ConstraintValidator::PRETTY_DATE],
@@ -73,3 +74,9 @@ public function __toString()
         return 'ccc';
     }
 }
+
+enum TestEnum
+{
+    case FirstCase;
+    case SecondCase;
+}