function do_unit_test($case)
{
    switch ($case) {
        case 1:
            $fArray = array();
            $cArray = array();
            respDBData($fArray, $cArray);
            break;
        case 2:
            respFieldList("pId");
            break;
        case 3:
            respFieldList("gSn");
            break;
        case 4:
            break;
    }
}
} else {
    $request_action = 'selectDb';
    //for test php correctness only
}
//echo "Action: " .$request_action."<br>";
switch ($request_action) {
    case "init":
        /* 
         * Display $recordLimit record of table data on body loading
         * and init the select option.  
         */
        //$recordLimit = $_POST["numOfRecord"];
        $recordLimit = 0;
        $respJSON["data"] = getRecentData($recordLimit);
        $respJSON["id_list"] = respFieldList("pId");
        $respJSON["dev_list"] = respFieldList("gSn");
        break;
        /*    
        case "checkDB": 
            $respJSON["has_updated"] = $_POST["userID"];
            break;            
        */
    /*    
    case "checkDB": 
        $respJSON["has_updated"] = $_POST["userID"];
        break;            
    */
    case "selectDb":
        //
        $fArray = array();
        $cKeys = array("pId", "measure_date", "gSn");