Calculating each exchange's fees (#188)

* Adds some constants for fee types
Adds some fee calculation in an attempt to be generic
Adds fee stuff to Bittrex
Adds fee stuff to bitstamp

* Fixes bitstamp fee calculation

* Tests
Tests all scenarios for GetFeeByType

* Adds method to wrapper
Adds err to response
Checks for err

* Adds support for Bittrex fees

* Adds maker/taker dynamic to fees
Updates tests
Adds bitmex fee support
Removes unused switch case scenarios to not waste space

* Adds bithumb support for fee calculation

* Adds Bitfinex fee support
Adds list of currencies as const strings
Sets up bitflyer

* Fixes arguments

* Greatly expands symbols
Adds Binance fee calculation support
Cleans up previous exchanges

* Fixes errors for fee calculations

* Adds ANX fee support

* Adds btcc fee support
Adds alphapoint fee wrapper support
Renames method to match "enum"
Uses symbols in tests, not inline strings

* Adds support for BTCMarkets fee calculation
Adds new method to retrieve fee amount from BTCMarkets
Adds new fee type struct: FeeBuilder
Updates ANX and BTCMarkets to use new FeeBuilder type struct
Standardises the tests to run when it comes to fee calculation

* Migrates all existing exchange fee to use new feebuilder type struct
Uses standard testing model

* Fixes unit tests

* Updates maker taker fees in test config

* Removes parallel from fee testing

* Removes more parallel from tests

* Adds coinbasepro fee support

* Adds Coinut fee support

* Adds Exmo fee support
Adds maker fee support to coinut
Introduces a type for fees and bank transfers to prevent random strings being used

* Adds partial bitflyer support
Moves bitflyer to feeBuilder struct

* Adds gateio fee support

* Adds Gemini fee support

* Adds hitbtc fee support

* Adds huobi fee support

* Adds HuobiHadax fee support

* Adds itbit fee support

* Adds partial kraken fee support with trading fees

* Finishes basic Kraken fee support

* Adds basic LakeBTC fee support

* Adds basic liqui fee support

* Adds localbitcoins fee support.......

* Adds basic okcoin fee support

* Adds simple OKEX fee support
Adds many new currency symbols
Fixes liqui's fees

* Adds poloniex fee support

* Adds fee support for Yobit

* Adds WEX fee support

* Adds ZB fee support

* Removes bad reference

* Improves accuracy of variable name

* trading fee method names are now consistent

(cherry picked from commit 21c82e8b90cae590cfd73d365d7be39e1a00e973)

* Fixes rebasing issues

* Fixes issues from rebase
Removes "IsTaker" as IsMaker bool can imply taker
Updates tests to actually work.

* Adds a zero to the test

* Fixes bitfinex api endpoints and fixes fee calculations

* Updates btcmarkets trading fee calculation

* Verifies tests with apis for all exchanges except coinbasepro, itbit and bitflyer
Removes taker fee test as taker is default

* Removes redundant all exchange wrapper error checks due to the error checks being redundant

* Addresses review comments:
- Renames variables
- Changes how functions return data
- Fixes typo

exchanges/itbit/itbit_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 
 	"github.com/thrasher-/gocryptotrader/config"
+	"github.com/thrasher-/gocryptotrader/currency/symbol"
+	exchange "github.com/thrasher-/gocryptotrader/exchanges"
 )
 
 var i ItBit
@@ -36,13 +38,6 @@ func TestSetup(t *testing.T) {
 	i.Setup(itbitConfig)
 }
 
-func TestGetFee(t *testing.T) {
-	t.Parallel()
-	if i.GetFee(true) != -0.1 || i.GetFee(false) != 0.5 {
-		t.Error("Test Failed - GetFee() error")
-	}
-}
-
 func TestGetTicker(t *testing.T) {
 	t.Parallel()
 	_, err := i.GetTicker("XBTUSD")
@@ -144,3 +139,93 @@ func TestWalletTransfer(t *testing.T) {
 		t.Error("Test Failed - WalletTransfer() error", err)
 	}
 }
+
+func setFeeBuilder() exchange.FeeBuilder {
+	return exchange.FeeBuilder{
+		Amount:              1,
+		Delimiter:           "_",
+		FeeType:             exchange.CryptocurrencyTradeFee,
+		FirstCurrency:       symbol.BTC,
+		SecondCurrency:      symbol.LTC,
+		IsMaker:             false,
+		PurchasePrice:       1,
+		CurrencyItem:        symbol.USD,
+		BankTransactionType: exchange.WireTransfer,
+	}
+}
+
+func TestGetFee(t *testing.T) {
+	t.Parallel()
+	var feeBuilder = setFeeBuilder()
+	// CryptocurrencyTradeFee Basic
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0.0025) || err != nil {
+		t.Error(err)
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0.002), resp)
+	}
+
+	// CryptocurrencyTradeFee High quantity
+	feeBuilder = setFeeBuilder()
+	feeBuilder.Amount = 1000
+	feeBuilder.PurchasePrice = 1000
+	if resp, err := i.GetFee(feeBuilder); resp != float64(2500) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(2500), resp)
+		t.Error(err)
+	}
+
+	// CryptocurrencyTradeFee IsMaker
+	feeBuilder = setFeeBuilder()
+	feeBuilder.IsMaker = true
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// CryptocurrencyTradeFee Negative purchase price
+	feeBuilder = setFeeBuilder()
+	feeBuilder.PurchasePrice = -1000
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+	// CryptocurrencyWithdrawalFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.CryptocurrencyWithdrawalFee
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// CryptocurrencyWithdrawalFee Invalid currency
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FirstCurrency = "hello"
+	feeBuilder.FeeType = exchange.CryptocurrencyWithdrawalFee
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// CyptocurrencyDepositFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.CyptocurrencyDepositFee
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// InternationalBankDepositFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.InternationalBankDepositFee
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// InternationalBankWithdrawalFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.InternationalBankWithdrawalFee
+	feeBuilder.CurrencyItem = symbol.USD
+	if resp, err := i.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+}