Gave data.go much needed love and split it up

frame_test.go

@@ -0,0 +1,31 @@
+package autotrader
+
+import (
+	"testing"
+	"time"
+)
+
+func TestDataFrame(t *testing.T) {
+	data := NewDOHLCVDataFrame()
+	if !data.ContainsDOHLCV() {
+		t.Fatalf("Expected data to contain DOHLCV columns")
+	}
+	if data.Len() != 0 {
+		t.Fatalf("Expected 0 rows, got %d", data.Len())
+	}
+
+	err := data.PushCandle(time.Date(2021, 5, 13, 0, 0, 0, 0, time.UTC), 0.8, 1.2, 0.6, 1.0, 1)
+	if err != nil {
+		t.Fatalf("Expected no error, got %s", err)
+	}
+	err = data.PushCandle(time.Date(2023, 5, 14, 0, 0, 0, 0, time.UTC), 1.0, 1.4, 0.8, 1.2, 1)
+	if err != nil {
+		t.Fatalf("Expected no error, got %s", err)
+	}
+	if data.Len() != 2 {
+		t.Fatalf("Expected 2 row, got %d", data.Len())
+	}
+	if data.Close(-1) != 1.2 {
+		t.Fatalf("Expected latest close to be 1.2, got %f", data.Close(-1))
+	}
+}