feat(orderbook): add assertions to removeOrder

This adds assertions to the `removeOrder` logic to ensure that we do not
remove any portion of an order that is currently on hold.

lib/orderbook/TradingPair.ts

@@ -180,18 +180,25 @@ class TradingPair {
 
   private removeOrder = <T extends Order>(orderId: string, maps: OrderSidesMaps<Order>, quantityToRemove?: number):
     { order: T, fullyRemoved: boolean } => {
+    assert(quantityToRemove === undefined || quantityToRemove > 0, 'quantityToRemove cannot be 0 or negative');
     const order = maps.buy.get(orderId) || maps.sell.get(orderId);
     if (!order) {
       throw errors.ORDER_NOT_FOUND(orderId);
     }
 
     if (quantityToRemove && quantityToRemove < order.quantity) {
       // if quantityToRemove is below the order quantity, reduce the order quantity
+      if (isOwnOrder(order)) {
+        assert(quantityToRemove <= order.quantity - order.hold, 'cannot remove more than available quantity after holds');
+      }
       order.quantity = order.quantity - quantityToRemove;
       this.logger.debug(`order quantity reduced by ${quantityToRemove}: ${orderId}`);
       return { order: { ...order, quantity: quantityToRemove } as T, fullyRemoved: false } ;
     } else {
       // otherwise, remove the order entirely
+      if (isOwnOrder(order)) {
+        assert(order.hold === 0, 'cannot remove an order with a hold');
+      }
       const list = order.isBuy ? maps.buy : maps.sell;
       list.delete(order.id);