Backtester: mini bug fixes (#1011)

* fixes errors with non-default strategies

* actually err = nil was silly

* fixes bug on sell side sizing, adjusts RSI strat

backtester/engine/backtest_types.go

@@ -16,7 +16,6 @@ import (
 
 var (
 	errNilConfig                   = errors.New("unable to setup backtester with nil config")
-	errInvalidConfigAsset          = errors.New("invalid asset in config")
 	errAmbiguousDataSource         = errors.New("ambiguous settings received. Only one data type can be set")
 	errNoDataSource                = errors.New("no data settings set in config")
 	errIntervalUnset               = errors.New("candle interval unset")

backtester/engine/setup.go

@@ -170,10 +170,10 @@ func NewFromConfig(cfg *config.Config, templatePath, output string, verbose bool
 			portfolioRisk.CurrencySettings[cfg.CurrencySettings[i].ExchangeName] = make(map[asset.Item]map[currency.Pair]*risk.CurrencySettings)
 		}
 		a := cfg.CurrencySettings[i].Asset
-		if err != nil {
+		if !a.IsValid() {
 			return nil, fmt.Errorf(
 				"%w for %v %v %v-%v. Err %v",
-				errInvalidConfigAsset,
+				asset.ErrNotSupported,
 				cfg.CurrencySettings[i].ExchangeName,
 				cfg.CurrencySettings[i].Asset,
 				cfg.CurrencySettings[i].Base,
@@ -293,7 +293,7 @@ func NewFromConfig(cfg *config.Config, templatePath, output string, verbose bool
 					return nil, err
 				}
 			default:
-				return nil, fmt.Errorf("%w: %v unsupported", errInvalidConfigAsset, a)
+				return nil, fmt.Errorf("%w: %v", asset.ErrNotSupported, a)
 			}
 		} else {
 			var bFunds, qFunds decimal.Decimal