diff --git a/code/FrameworkTestFileExtension.php b/code/FrameworkTestFileExtension.php
index dcef003..b4c4fbe 100644
--- a/code/FrameworkTestFileExtension.php
+++ b/code/FrameworkTestFileExtension.php
@@ -1,6 +1,6 @@
 <?php
 class FrameworkTestFileExtension extends DataExtension {
-	static $has_one = array(
+	private static $has_one = array(
 		'Company' => 'Company',
 		'BasicFieldsTestPage' => 'BasicFieldsTestPage'
 	);