diff --git a/lib/Cake/Test/Case/Utility/CakeNumberTest.php b/lib/Cake/Test/Case/Utility/CakeNumberTest.php
index a026099c77f..6c1c5d30656 100644
--- a/lib/Cake/Test/Case/Utility/CakeNumberTest.php
+++ b/lib/Cake/Test/Case/Utility/CakeNumberTest.php
@@ -491,7 +491,7 @@ public function testToReadableSize() {
  */
 	public function testReadableSizeLocalized() {
 		$restore = setlocale(LC_NUMERIC, 0);
-		setlocale(LC_NUMERIC, 'nl_NL');
+		setlocale(LC_NUMERIC, 'de_DE');
 		$result = $this->Number->toReadableSize(1321205);
 		$this->assertEquals('1,26 MB', $result);