--- a/server/src/tests/libraries/UtilsTest.php	Fri Nov 27 17:59:36 2015 +0100
+++ b/server/src/tests/libraries/UtilsTest.php	Tue Dec 01 13:33:08 2015 +0100
@@ -25,4 +25,10 @@
         $ms = Utils::iso8601IntervalToMillis("P1Y1M1DT1H1M1S");
         $this->assertEquals(34277461000, $ms, "duration must be 3427746100");
     }
+
+    public function testiso8601IntervalToMillisNull() {
+        $ms = Utils::iso8601IntervalToMillis(null);
+        $this->assertNull($ms, "duration must be null");
+    }
+
 }