codebase: Cleanup various things (#1935)

* codebase: Rid base64/hex to string common funcs

* codebase: Rid local scope variable usage and other improvements

* codebase: Refactor currency pair usage across multiple exchanges

- Updated HitBTC tests to use the new currency pair format.
- Modified Kraken futures types to use currency.Pair instead of string for Symbol.
- Adjusted Kraken wrapper methods to handle currency pairs correctly.
- Refined OKX tests and types to utilize currency.Pair for instrument IDs.
- Enhanced Poloniex tests to consistently use predefined currency pairs.
- Streamlined order and orderbook tests to replace string pairs with currency.NewBTCUSD().
- Improved Yobit tests to utilize a standardized currency pair format.
- Updated validator wrapper to use currency pairs directly instead of string conversions.

* codebase: Use types.Number where possible

* refactor: update PayoutFee type to types.Number for consistency

* Refactor: Remove crypto functions to use standard library and other minor changes

- Removed custom crypto functions for SHA256, SHA512, and MD5 from the common/crypto package.
- Replaced usages of removed functions with standard library implementations in various files including:
  - cmd/websocket_client/main.go
  - engine/apiserver.go
  - exchanges/kraken/kraken.go
  - exchanges/lbank/lbank.go
  - exchanges/okx/okx_business_websocket.go
  - exchanges/kucoin/kucoin_websocket.go
  - gctscript/vm/vm.go
- Updated tests to reflect changes in the crypto functions.
- Renamed several functions for clarity, particularly in the context of order book updates across multiple exchanges.

* refactor: replace assert with require for consistency in test assertions

* refactor: Improve Binance futures candlestick test, standardise orderbook update function names and improve test parallelism

* refactor: Replace require.Len with require.Equal for better output in TestGetFuturesKlineData

exchanges/yobit/yobit.go

@@ -2,6 +2,7 @@ package yobit
 
 import (
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"net/http"
@@ -310,16 +311,14 @@ func (y *Yobit) SendAuthenticatedHTTPRequest(ctx context.Context, ep exchange.UR
 		params.Set("method", path)
 
 		encoded := params.Encode()
-		hmac, err := crypto.GetHMAC(crypto.HashSHA512,
-			[]byte(encoded),
-			[]byte(creds.Secret))
+		hmac, err := crypto.GetHMAC(crypto.HashSHA512, []byte(encoded), []byte(creds.Secret))
 		if err != nil {
 			return nil, err
 		}
 
 		headers := make(map[string]string)
 		headers["Key"] = creds.Key
-		headers["Sign"] = crypto.HexEncodeToString(hmac)
+		headers["Sign"] = hex.EncodeToString(hmac)
 		headers["Content-Type"] = "application/x-www-form-urlencoded"
 
 		return &request.Item{

exchanges/yobit/yobit_test.go

@@ -30,6 +30,8 @@ const (
 	canManipulateRealOrders = false
 )
 
+var testPair = currency.NewBTCUSD().Format(currency.PairFormat{Delimiter: "_"})
+
 func TestMain(m *testing.M) {
 	y.SetDefaults()
 	yobitConfig := config.GetConfig()
@@ -71,26 +73,20 @@ func TestGetInfo(t *testing.T) {
 
 func TestGetTicker(t *testing.T) {
 	t.Parallel()
-	_, err := y.GetTicker(t.Context(), "btc_usd")
-	if err != nil {
-		t.Error("GetTicker() error", err)
-	}
+	_, err := y.GetTicker(t.Context(), testPair.String())
+	assert.NoError(t, err, "GetTicker should not error")
 }
 
 func TestGetDepth(t *testing.T) {
 	t.Parallel()
-	_, err := y.GetDepth(t.Context(), "btc_usd")
-	if err != nil {
-		t.Error("GetDepth() error", err)
-	}
+	_, err := y.GetDepth(t.Context(), testPair.String())
+	assert.NoError(t, err, "GetDepth should not error")
 }
 
 func TestGetTrades(t *testing.T) {
 	t.Parallel()
-	_, err := y.GetTrades(t.Context(), "btc_usd")
-	if err != nil {
-		t.Error("GetTrades() error", err)
-	}
+	_, err := y.GetTrades(t.Context(), testPair.String())
+	assert.NoError(t, err, "GetTrades should not error")
 }
 
 func TestGetAccountInfo(t *testing.T) {
@@ -507,38 +503,19 @@ func TestGetDepositAddress(t *testing.T) {
 }
 
 func TestGetRecentTrades(t *testing.T) {
-	currencyPair, err := currency.NewPairFromString("btc_usd")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = y.GetRecentTrades(t.Context(), currencyPair, asset.Spot)
-	if err != nil {
-		t.Error(err)
-	}
+	_, err := y.GetRecentTrades(t.Context(), testPair, asset.Spot)
+	assert.NoError(t, err, "GetRecentTrades should not error")
 }
 
 func TestGetHistoricTrades(t *testing.T) {
-	currencyPair, err := currency.NewPairFromString("btc_usd")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = y.GetHistoricTrades(t.Context(),
-		currencyPair, asset.Spot, time.Now().Add(-time.Minute*15), time.Now())
-	if err != nil && err != common.ErrFunctionNotSupported {
-		t.Error(err)
-	}
+	_, err := y.GetHistoricTrades(t.Context(), testPair, asset.Spot, time.Now().Add(-time.Minute*15), time.Now())
+	assert.ErrorIs(t, err, common.ErrFunctionNotSupported)
 }
 
 func TestUpdateTicker(t *testing.T) {
 	t.Parallel()
-	cp, err := currency.NewPairFromString("ETH_BTC")
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = y.UpdateTicker(t.Context(), cp, asset.Spot)
-	if err != nil {
-		t.Error(err)
-	}
+	_, err := y.UpdateTicker(t.Context(), testPair, asset.Spot)
+	assert.NoError(t, err, "UpdateTicker should not error")
 }
 
 func TestUpdateTickers(t *testing.T) {