Offline worst case trade fees (#274)

* Really basic getSimulated fee function everywhere

* Worst case fees for all exchanges

* Adds tests, fixes comment spacing. Adds wrapper logic. Makes test api key var name consistent. Removes some okcoin ETT tests

* Removes redundant functions

* linting issues. Fixes introduces huobi issues

* More linting

* Stops trying to hide ETT problems, uses iota

* Skips ETT tests for now

exchanges/zb/zb.go

@@ -422,6 +422,8 @@ func (z *ZB) GetFee(feeBuilder *exchange.FeeBuilder) (float64, error) {
 		fee = calculateTradingFee(feeBuilder.PurchasePrice, feeBuilder.Amount)
 	case exchange.CryptocurrencyWithdrawalFee:
 		fee = getWithdrawalFee(feeBuilder.Pair.Base)
+	case exchange.OfflineTradeFee:
+		fee = getOfflineTradeFee(feeBuilder.PurchasePrice, feeBuilder.Amount)
 	}
 	if fee < 0 {
 		fee = 0
@@ -430,6 +432,11 @@ func (z *ZB) GetFee(feeBuilder *exchange.FeeBuilder) (float64, error) {
 	return fee, nil
 }
 
+// getOfflineTradeFee calculates the worst case-scenario trading fee
+func getOfflineTradeFee(price, amount float64) float64 {
+	return 0.002 * price * amount
+}
+
 func calculateTradingFee(purchasePrice, amount float64) (fee float64) {
 	fee = 0.002
 	return fee * amount * purchasePrice

exchanges/zb/zb_test.go

@@ -138,6 +138,21 @@ func setFeeBuilder() *exchange.FeeBuilder {
 	}
 }
 
+// TestGetFeeByTypeOfflineTradeFee logic test
+func TestGetFeeByTypeOfflineTradeFee(t *testing.T) {
+	var feeBuilder = setFeeBuilder()
+	z.GetFeeByType(feeBuilder)
+	if apiKey == "" || apiSecret == "" {
+		if feeBuilder.FeeType != exchange.OfflineTradeFee {
+			t.Errorf("Expected %v, received %v", exchange.OfflineTradeFee, feeBuilder.FeeType)
+		}
+	} else {
+		if feeBuilder.FeeType != exchange.CryptocurrencyTradeFee {
+			t.Errorf("Expected %v, received %v", exchange.CryptocurrencyTradeFee, feeBuilder.FeeType)
+		}
+	}
+}
+
 func TestGetFee(t *testing.T) {
 	z.SetDefaults()
 	TestSetup(t)

exchanges/zb/zb_wrapper.go

@@ -307,6 +307,10 @@ func (z *ZB) GetWebsocket() (*exchange.Websocket, error) {
 
 // GetFeeByType returns an estimate of fee based on type of transaction
 func (z *ZB) GetFeeByType(feeBuilder *exchange.FeeBuilder) (float64, error) {
+	if (z.APIKey == "" || z.APISecret == "") && // Todo check connection status
+		feeBuilder.FeeType == exchange.CryptocurrencyTradeFee {
+		feeBuilder.FeeType = exchange.OfflineTradeFee
+	}
 	return z.GetFee(feeBuilder)
 }