diff --git a/lib/Cake/Test/Case/Utility/ValidationTest.php b/lib/Cake/Test/Case/Utility/ValidationTest.php
index bed0f438ba3..90de95ca442 100644
--- a/lib/Cake/Test/Case/Utility/ValidationTest.php
+++ b/lib/Cake/Test/Case/Utility/ValidationTest.php
@@ -1973,6 +1973,7 @@ public function testNaturalNumber() {
 		$this->assertFalse(Validation::naturalNumber('-2'));
 		$this->assertFalse(Validation::naturalNumber(-2));
 		$this->assertFalse(Validation::naturalNumber('0'));
+		$this->assertFalse(Validation::naturalNumber('050'));
 
 		$this->assertTrue(Validation::naturalNumber('2'));
 		$this->assertTrue(Validation::naturalNumber(49));