exchange: add SetRequester to exchange Base (#1095)

* add setRequester to exchange Base

* add tests

* fix lint

* Update exchange_test.go

exchanges/exchange.go

@@ -21,6 +21,7 @@ import (
 	"github.com/thrasher-corp/gocryptotrader/exchanges/margin"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/order"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/protocol"
+	"github.com/thrasher-corp/gocryptotrader/exchanges/request"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/stream"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/trade"
 	"github.com/thrasher-corp/gocryptotrader/log"
@@ -47,6 +48,16 @@ var (
 	errSymbolCannotBeMatched             = errors.New("symbol cannot be matched")
 )
 
+// SetRequester sets the instance of the requester
+func (b *Base) SetRequester(r *request.Requester) error {
+	if r == nil {
+		return fmt.Errorf("%s cannot set requester, no requester provided", b.Name)
+	}
+
+	b.Requester = r
+	return nil
+}
+
 // SetClientProxyAddress sets a proxy address for REST and websocket requests
 func (b *Base) SetClientProxyAddress(addr string) error {
 	if addr == "" {

exchanges/exchange_test.go

@@ -2616,3 +2616,31 @@ func TestGetPairAndAssetTypeRequestFormatted(t *testing.T) {
 		t.Fatalf("received: '%v' but expected: '%v'", p, expected)
 	}
 }
+
+func TestSetRequester(t *testing.T) {
+	t.Parallel()
+
+	b := Base{
+		Config:    &config.Exchange{Name: "kitties"},
+		Requester: nil,
+	}
+
+	err := b.SetRequester(nil)
+	if err == nil {
+		t.Fatal("error cannot be nil")
+	}
+
+	requester, err := request.New("testingRequester", common.NewHTTPClientWithTimeout(0))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = b.SetRequester(requester)
+	if err != nil {
+		t.Fatalf("expected no error, received %v", err)
+	}
+
+	if b.Requester == nil {
+		t.Fatal("requester not set correctly")
+	}
+}