回测火币数据，以及在wexapp模拟盘交易，都得到类似下面的运行结果：
如果限价下单，那么exchange.Buy(6840, 5)就是以6840的价格买入5个btc。 如果市价下单，那么exchange.Buy(-1, 5)就是以市价、花费5个usdt买入btc。
策略代码：https://www.fmz.com/m/edit-strategy/191349
2020年4月5日
/*backtest
start: 2020-01-01 00:00:00
end: 2020-04-01 00:00:00
period: 1d
exchanges: [{"eid":"Huobi","currency":"BTC_USD","balance":1000000,"stocks":0}]
*/
var id, order, buyAmount, lastPrice;
function main() {
Log(exchange.GetAccount());
lastPrice = parseInt(exchange.GetTicker().Last);
id = exchange.Buy(lastPrice + 50, 5); // 限价买入5个BTC，买入价是当前最新价格+50
Log(order = exchange.GetOrder(id));
buyAmount = parseFloat(order.DealAmount);
Log(exchange.GetAccount());
Sleep(1000);
last_price = parseInt(exchange.GetTicker().Last);
id = exchange.Sell(lastPrice - 50, buyAmount); // 限价卖出5个BTC，卖出价是当前最新价格-50
Log(order = exchange.GetOrder(id));
Log(exchange.GetAccount());
Sleep(1000);
id = exchange.Buy(-1, 5); // 市价买入BTC，成交量是5个usdt
Sleep(1000);
Log(order = exchange.GetOrder(id));
buyAmount = parseFloat(order.DealAmount);
Log(exchange.GetAccount());
Sleep(1000);
id = exchange.Sell(-1, buyAmount); // 市价卖出BTC，成交量是刚才买入的BTC
Sleep(1000);
Log(order = exchange.GetOrder(id));
Log(exchange.GetAccount());
}