Kucoin: Fix intermittent TestPushData failure (#2116)

* Testing: Fix FixtureToDataHandlerWithErrors logging []byte

* Kucoin: Fix global mutexes and maps

Highlighted by:
```
go test -count 2 -run TestPushData
```

that the second run wasn't finding a futures orderbook, because the
instance had changed but kucoin was using a global map

exchanges/kucoin/kucoin.go

@@ -31,11 +31,12 @@ import (
 // Exchange implements exchange.IBotExchange and contains additional specific api methods for interacting with Kucoin
 type Exchange struct {
 	exchange.Base
+	obmMutex                     sync.Mutex
 	obm                          *orderbookManager
+	fetchedFuturesOrderbookMutex sync.Mutex
+	fetchedFuturesOrderbook      map[string]bool
 }
 
-var locker sync.Mutex
-
 const (
 	kucoinAPIURL = "https://api.kucoin.com/api"
 	tradeBaseURL = "https://www.kucoin.com/"

exchanges/kucoin/kucoin_test.go

@@ -72,7 +72,6 @@ func TestMain(m *testing.M) {
 		asset.Margin:  marginTradablePair,
 		asset.Futures: futuresTradablePair,
 	}
-	fetchedFuturesOrderbook = map[string]bool{}
 
 	os.Exit(m.Run())
 }
@@ -4088,13 +4087,14 @@ func TestGetCurrencyTradeURL(t *testing.T) {
 // testInstance returns a local Kucoin for isolated testing
 func testInstance(tb testing.TB) *Exchange {
 	tb.Helper()
-	kucoin := new(Exchange)
-	require.NoError(tb, testexch.Setup(kucoin), "Test instance Setup must not error")
-	kucoin.obm = &orderbookManager{
+	e := new(Exchange)
+	require.NoError(tb, testexch.Setup(e), "Test instance Setup must not error")
+	e.obm = &orderbookManager{
 		state: make(map[currency.Code]map[currency.Code]map[asset.Item]*update),
 		jobs:  make(chan job, maxWSOrderbookJobs),
 	}
-	return kucoin
+	e.fetchedFuturesOrderbook = map[string]bool{}
+	return e
 }
 
 func TestGetTradingPairActualFees(t *testing.T) {

exchanges/kucoin/kucoin_websocket.go

@@ -30,11 +30,6 @@ import (
 	"github.com/thrasher-corp/gocryptotrader/log"
 )
 
-var (
-	fetchedFuturesOrderbookMutex sync.Mutex
-	fetchedFuturesOrderbook      map[string]bool
-)
-
 const (
 	publicBullets  = "/v1/bullet-public"
 	privateBullets = "/v1/bullet-private"
@@ -121,9 +116,9 @@ func (e *Exchange) WsConnect() error {
 	if !e.Websocket.IsEnabled() || !e.IsEnabled() {
 		return websocket.ErrWebsocketNotEnabled
 	}
-	fetchedFuturesOrderbookMutex.Lock()
-	fetchedFuturesOrderbook = map[string]bool{}
-	fetchedFuturesOrderbookMutex.Unlock()
+	e.fetchedFuturesOrderbookMutex.Lock()
+	e.fetchedFuturesOrderbook = map[string]bool{}
+	e.fetchedFuturesOrderbookMutex.Unlock()
 	var dialer gws.Dialer
 	dialer.HandshakeTimeout = e.Config.HTTPTimeout
 	dialer.Proxy = http.ProxyFromEnvironment
@@ -503,12 +498,12 @@ func (e *Exchange) processFuturesMarkPriceAndIndexPrice(respData []byte, instrum
 
 // ensureFuturesOrderbookSnapshotLoaded makes sure an initial futures orderbook snapshot is loaded
 func (e *Exchange) ensureFuturesOrderbookSnapshotLoaded(ctx context.Context, symbol string) error {
-	fetchedFuturesOrderbookMutex.Lock()
-	defer fetchedFuturesOrderbookMutex.Unlock()
-	if fetchedFuturesOrderbook[symbol] {
+	e.fetchedFuturesOrderbookMutex.Lock()
+	defer e.fetchedFuturesOrderbookMutex.Unlock()
+	if e.fetchedFuturesOrderbook[symbol] {
 		return nil
 	}
-	fetchedFuturesOrderbook[symbol] = true
+	e.fetchedFuturesOrderbook[symbol] = true
 	enabledPairs, err := e.GetEnabledPairs(asset.Futures)
 	if err != nil {
 		return err
@@ -1097,8 +1092,8 @@ type job struct {
 
 // setupOrderbookManager sets up the orderbook manager for websocket orderbook data handling.
 func (e *Exchange) setupOrderbookManager(ctx context.Context) {
-	locker.Lock()
-	defer locker.Unlock()
+	e.obmMutex.Lock()
+	defer e.obmMutex.Unlock()
 	if e.obm == nil {
 		e.obm = &orderbookManager{
 			state: make(map[currency.Code]map[currency.Code]map[asset.Item]*update),

internal/testing/exchange/exchange.go

@@ -133,7 +133,7 @@ func MockWsInstance[T any, PT interface {
 // FixtureError contains an error and the message that caused it
 type FixtureError struct {
 	Err error
-	Msg []byte
+	Msg string
 }
 
 // FixtureToDataHandler squirts the contents of a file to a reader function (probably e.wsHandleData) and asserts no errors are returned
@@ -163,7 +163,7 @@ func FixtureToDataHandlerWithErrors(tb testing.TB, fixturePath string, reader fu
 		if err := reader(tb.Context(), msg); err != nil {
 			errs = append(errs, FixtureError{
 				Err: err,
-				Msg: msg,
+				Msg: string(msg),
 			})
 		}
 	}