diff --git a/tests/unit/TestStreamWrapper.php b/tests/unit/TestStreamWrapper.php
index 0d2a7bfc..0e698107 100644
--- a/tests/unit/TestStreamWrapper.php
+++ b/tests/unit/TestStreamWrapper.php
@@ -36,6 +36,8 @@ class TestStreamWrapper {
 
     public static $map = [];
 
+    public $context;
+
     protected $_protocol;
 
     /** @var string */