@Test
public void testMapFunctionWithNumberItemAndCountFunction() {

    // testing Group:Number:Count(".*hello.*")
    NumberItem item1 = new NumberItem("item1");
    GroupFunctionDTO gFuncDTO = new GroupFunctionDTO();
    gFuncDTO.name = "COUNT";
    gFuncDTO.params = new String[] { ".*hello.*" };
    GroupFunction gFunc = ItemDTOMapper.mapFunction(item1, gFuncDTO);
    assertThat(gFunc, instanceOf(ArithmeticGroupFunction.Count.class));
    assertThat(gFunc.getParameters().length, is(1));
    assertThat(gFunc.getParameters()[0], instanceOf(StringType.class));
}