@Test
    public void test_get_arrayValues() {
        String arrayKey = "array.values";
        String arrayValue = "value1,value2,value3";

        System.setProperty(Constants.FESS_CONFIG_PREFIX + arrayKey, arrayValue);

        try {
            String value = fessConfig.get(arrayKey);
            assertEquals(arrayValue, value);
        } finally {

        StringBuilder buf = new StringBuilder();
        double[] values = { 1.5, 2.3, 3.7 };
        Supplier<Object> supplier = () -> values;

        monitorTarget.append(buf, "arrayKey", supplier);
        assertEquals("\"arrayKey\":[1.5, 2.3, 3.7]", buf.toString());
    }

    // Test append method with empty double array
    @Test
    public void test_append_emptyDoubleArray() {

                    value);
        }

        final Map<String, Object> source = new HashMap<>();
        source.put(FieldNames.ARRAY_KEY, key);
        source.put(FieldNames.ARRAY_VALUE, value);
        source.put(FieldNames.TIMESTAMP, DateTimeFormatter.ISO_INSTANT.format(ZonedDateTime.now()));

                    elevateWord.getElevateWord(), elevateWord.getBoost());
        }

        final Map<String, Object> source = new HashMap<>();
        source.put(FieldNames.ARRAY_KEY, ELEVATE_WORD_SETTINGS_KEY);
        source.put(FieldNames.ARRAY_VALUE, elevateWord.getElevateWord());
        source.put(ELEVATE_WORD_BOOST, elevateWord.getBoost());