diff --git a/tests/test.php b/tests/test.php
index 9a99e4d..25a24d6 100644
--- a/tests/test.php
+++ b/tests/test.php
@@ -15,6 +15,9 @@ if (in_array('-f', $argv)) {
 	echoTitle("opcache reset");
 }
 
+// create the trees directory if it doesn't exist
+if (!is_dir(TREES)) mkdir(TREES);
+
 $r = new SegmentRouter();
 
 // Blog lookups