Do not depend on RB for utility test

Author: driusan

php/libraries/Utility.class.inc

@@ -851,8 +851,10 @@ class Utility
                 "Input must be a valid date/time string: $e"
             );
         }
+
+        $factory = \NDB_Factory::singleton();
         return $dt->format(
-            \NDB_Config::singleton()->getSetting('dateDisplayFormat')
+            $factory->config()->getSetting('dateDisplayFormat')
             ?? DateTime::ATOM
         );
     }

test/unittests/UtilityTest.php

@@ -1136,6 +1136,13 @@ public function testRandomString()
     public function testToDateDisplayFormat()
     {
         $this->_setMockDB();
+
+        $config = $this->getMockBuilder("\NDB_Config")->getMock();
+        $config->expects($this->any())
+            ->method('getSetting')
+            ->willReturn('Y-m-d H:i:s');
+        $this->_mockFactory->setConfig($config);
+
         $date = "2000-01-01";
         $this->assertEquals(
             "2000-01-01 00:00:00",