Adding upstream version 2.1.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

histogram_series_test.go

@@ -0,0 +1,31 @@
+package chart
+
+import (
+	"testing"
+
+	"github.com/wcharczuk/go-chart/v2/testutil"
+)
+
+func TestHistogramSeries(t *testing.T) {
+	// replaced new assertions helper
+
+	cs := ContinuousSeries{
+		Name:    "Test Series",
+		XValues: LinearRange(1.0, 20.0),
+		YValues: LinearRange(10.0, -10.0),
+	}
+
+	hs := HistogramSeries{
+		InnerSeries: cs,
+	}
+
+	for x := 0; x < hs.Len(); x++ {
+		csx, csy := cs.GetValues(0)
+		hsx, hsy1, hsy2 := hs.GetBoundedValues(0)
+		testutil.AssertEqual(t, csx, hsx)
+		testutil.AssertTrue(t, hsy1 > 0)
+		testutil.AssertTrue(t, hsy2 <= 0)
+		testutil.AssertTrue(t, csy < 0 || (csy > 0 && csy == hsy1))
+		testutil.AssertTrue(t, csy > 0 || (csy < 0 && csy == hsy2))
+	}
+}