Refactoring.

components/device-mgt/org.wso2.carbon.device.mgt.api/src/test/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceTypeManagementServiceTest.java

@@ -109,7 +109,7 @@ public class DeviceTypeManagementServiceTest {
         Mockito.when(this.deviceManagementProviderService.getAvailableDeviceTypes()).thenThrow(new
                 DeviceManagementException());
 
-        Response response = this.deviceTypeManagementService.getDeviceTypes("");
+        Response response = this.deviceTypeManagementService.getDeviceTypes(MODIFIED_SINCE);
         Assert.assertNotNull(response);
         Assert.assertEquals(response.getStatus(), Response.Status.INTERNAL_SERVER_ERROR.getStatusCode());
         Mockito.reset(deviceManagementProviderService);