backtester: Improve test coverage (#717)

* Improve config test coverage

* Improve common test coverage

* Improve data test coverage

* Silence false positives on table tests

backtester/data/data_test.go

@@ -2,17 +2,26 @@ package data
 
 import (
 	"testing"
+	"time"
 
 	"github.com/thrasher-corp/gocryptotrader/currency"
 	"github.com/thrasher-corp/gocryptotrader/exchanges/asset"
+	"github.com/thrasher-corp/gocryptotrader/exchanges/kline"
 )
 
 const testExchange = "binance"
 
+type fakeDataHandler struct {
+	time int
+}
+
 func TestBaseDataFunctions(t *testing.T) {
 	t.Parallel()
 	var d Base
-	d.Latest()
+	latest := d.Latest()
+	if latest != nil {
+		t.Error("expected nil")
+	}
 	d.Next()
 	o := d.Offset()
 	if o != 0 {
@@ -27,8 +36,14 @@ func TestBaseDataFunctions(t *testing.T) {
 	if o != 0 {
 		t.Error("expected 0")
 	}
-	d.List()
-	d.History()
+	list := d.List()
+	if list != nil {
+		t.Error("expected nil")
+	}
+	history := d.History()
+	if history != nil {
+		t.Error("expected nil")
+	}
 	d.SetStream(nil)
 	st := d.GetStream()
 	if st != nil {
@@ -48,6 +63,55 @@ func TestSetup(t *testing.T) {
 	}
 }
 
+func TestStream(t *testing.T) {
+	var d Base
+	var f fakeDataHandler
+
+	// shut up coverage report
+	f.GetOffset()
+	f.SetOffset(1)
+	f.IsEvent()
+	f.Pair()
+	f.GetExchange()
+	f.GetInterval()
+	f.GetAssetType()
+	f.GetReason()
+	f.AppendReason("fake")
+	f.ClosePrice()
+	f.HighPrice()
+	f.LowPrice()
+	f.OpenPrice()
+
+	d.AppendStream(fakeDataHandler{time: 1})
+	d.AppendStream(fakeDataHandler{time: 4})
+	d.AppendStream(fakeDataHandler{time: 10})
+	d.AppendStream(fakeDataHandler{time: 2})
+	d.AppendStream(fakeDataHandler{time: 20})
+
+	d.SortStream()
+
+	f = d.Next().(fakeDataHandler)
+	if f.time != 1 {
+		t.Error("expected 1")
+	}
+	f = d.Next().(fakeDataHandler)
+	if f.time != 2 {
+		t.Error("expected 2")
+	}
+	f = d.Next().(fakeDataHandler)
+	if f.time != 4 {
+		t.Error("expected 4")
+	}
+	f = d.Next().(fakeDataHandler)
+	if f.time != 10 {
+		t.Error("expected 10")
+	}
+	f = d.Next().(fakeDataHandler)
+	if f.time != 20 {
+		t.Error("expected 20")
+	}
+}
+
 func TestSetDataForCurrency(t *testing.T) {
 	t.Parallel()
 	d := HandlerPerCurrency{}
@@ -107,3 +171,58 @@ func TestReset(t *testing.T) {
 		t.Error("expected nil")
 	}
 }
+
+// methods that satisfy the common.DataEventHandler interface
+func (t fakeDataHandler) GetOffset() int64 {
+	return 0
+}
+
+func (t fakeDataHandler) SetOffset(int64) {
+}
+
+func (t fakeDataHandler) IsEvent() bool {
+	return false
+}
+
+func (t fakeDataHandler) GetTime() time.Time {
+	return time.Now().Add(time.Hour * time.Duration(t.time))
+}
+
+func (t fakeDataHandler) Pair() currency.Pair {
+	return currency.NewPair(currency.BTC, currency.USD)
+}
+
+func (t fakeDataHandler) GetExchange() string {
+	return "fake"
+}
+
+func (t fakeDataHandler) GetInterval() kline.Interval {
+	return kline.Interval(time.Minute)
+}
+
+func (t fakeDataHandler) GetAssetType() asset.Item {
+	return asset.Spot
+}
+
+func (t fakeDataHandler) GetReason() string {
+	return "fake"
+}
+
+func (t fakeDataHandler) AppendReason(string) {
+}
+
+func (t fakeDataHandler) ClosePrice() float64 {
+	return 0
+}
+
+func (t fakeDataHandler) HighPrice() float64 {
+	return 0
+}
+
+func (t fakeDataHandler) LowPrice() float64 {
+	return 0
+}
+
+func (t fakeDataHandler) OpenPrice() float64 {
+	return 0
+}