}

    // Test getAsString with default value
    @Test
    public void test_getAsStringWithDefaultValue() {
        dataStoreParams.put("existingKey", "existingValue");
        assertEquals("existingValue", dataStoreParams.getAsString("existingKey", "defaultValue"));

        assertNull(dataStoreParams.getAsString("nonExistentKey"));

        // Test loading into existing map
        paramMap = new HashMap<>();
        paramMap.put("existing", "existingValue");
        configParam = "key1=value1\nkey2=value2";
        ParameterUtil.loadConfigParams(paramMap, configParam);
        assertEquals(3, paramMap.size());
        assertEquals("existingValue", paramMap.get("existing"));
        assertEquals("value1", paramMap.get("key1"));