diff --git a/tests/lib/SimpleSAML/Utils/ArraysTest.php b/tests/lib/SimpleSAML/Utils/ArraysTest.php
index e32c8aee22d34df11b430516d252bf760c94d237..c4a38726aef8839a2e1458d99773e2b088bddb0d 100644
--- a/tests/lib/SimpleSAML/Utils/ArraysTest.php
+++ b/tests/lib/SimpleSAML/Utils/ArraysTest.php
@@ -42,6 +42,9 @@ class ArraysTest extends \PHPUnit_Framework_TestCase
      */
     public function testTranspose()
     {
+        // check not array
+        $this->assertFalse(Arrays::transpose('string'));
+
         // check bad arrays
         $this->assertFalse(
             Arrays::transpose(array('1', '2', '3')),