Wrapped enum declaration in eval function for better backward compatibility.

Author: gordinskiy

tests/AssertTest.php

@@ -871,8 +871,12 @@ public function __toString()
 const ENUM_INTRODUCTION_VERSION_ID = 80100;
 
 if (PHP_VERSION_ID >= ENUM_INTRODUCTION_VERSION_ID) {
-    enum TestEnum
-    {
-        case CaseName;
-    }
+    eval('
+        namespace '.__NAMESPACE__.';
+
+        enum TestEnum
+        {
+            case CaseName;
+        }
+    ');
 }