@Test
 public void convertValueString() {
   FieldTypeEnum fieldTypeEnum = FieldTypeEnum.STRING;
   String value = "test";
   assertTrue(highchartSeriesUtil.convertValue(fieldTypeEnum, value) instanceof String);
   assertEquals(highchartSeriesUtil.convertValue(fieldTypeEnum, value), value);
 }
 @Test
 public void convertValueInt() {
   FieldTypeEnum fieldTypeEnum = FieldTypeEnum.INT;
   Integer value = Integer.valueOf("1");
   assertTrue(highchartSeriesUtil.convertValue(fieldTypeEnum, value) instanceof Integer);
   assertEquals(highchartSeriesUtil.convertValue(fieldTypeEnum, value), value);
 }
 @Test
 public void convertValueDate() {
   FieldTypeEnum fieldTypeEnum = FieldTypeEnum.DATE;
   Date value = mock(Date.class);
   assertTrue(highchartSeriesUtil.convertValue(fieldTypeEnum, value) instanceof Long);
 }