From f952019abdce1c85ebf7a3d93e929d397b65fe1d Mon Sep 17 00:00:00 2001
From: Todd <todd@baliance.com>
Date: Tue, 5 Sep 2017 20:53:11 -0400
Subject: [PATCH] chart: more docs

---
 chart/axis.go           |  2 ++
 chart/axis_test.go      | 20 ++++++++++++++++++++
 chart/barchartseries.go |  4 +++-
 3 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 chart/axis_test.go

diff --git a/chart/axis.go b/chart/axis.go
index a73fd0dc..809cb6fa 100644
--- a/chart/axis.go
+++ b/chart/axis.go
@@ -7,6 +7,8 @@
 
 package chart
 
+// Axis is the interface implemented by different axes when assigning to a
+// chart.
 type Axis interface {
 	AxisID() uint32
 }
diff --git a/chart/axis_test.go b/chart/axis_test.go
new file mode 100644
index 00000000..015e6b9c
--- /dev/null
+++ b/chart/axis_test.go
@@ -0,0 +1,20 @@
+// Copyright 2017 Baliance. All rights reserved.
+//
+// Use of this source code is governed by the terms of the Affero GNU General
+// Public License version 3.0 as published by the Free Software Foundation and
+// appearing in the file LICENSE included in the packaging of this file. A
+// commercial license can be purchased by contacting sales@baliance.com.
+
+package chart_test
+
+import (
+	"testing"
+
+	"baliance.com/gooxml/chart"
+)
+
+func TestNullAxis(t *testing.T) {
+	if chart.NullAxis.AxisID() != 0 {
+		t.Errorf("expected null axis to have ID 0, go %d", chart.NullAxis.AxisID())
+	}
+}
diff --git a/chart/barchartseries.go b/chart/barchartseries.go
index 77ad1985..8b57daf0 100644
--- a/chart/barchartseries.go
+++ b/chart/barchartseries.go
@@ -13,6 +13,7 @@ import (
 	crt "baliance.com/gooxml/schema/schemas.openxmlformats.org/drawingml/2006/chart"
 )
 
+// BarChartSeries is a series to be used on a bar chart.
 type BarChartSeries struct {
 	x *crt.CT_BarSer
 }
@@ -26,7 +27,7 @@ func (c BarChartSeries) X() *crt.CT_BarSer {
 func (c BarChartSeries) InitializeDefaults() {
 }
 
-// SetText sets the series text
+// SetText sets the series text.
 func (c BarChartSeries) SetText(s string) {
 	c.x.Tx = crt.NewCT_SerTx()
 	c.x.Tx.Choice.V = &s
@@ -39,6 +40,7 @@ func (c BarChartSeries) CategoryAxis() AxisDataSource {
 	return MakeAxisDataSource(c.x.Cat)
 }
 
+//
 func (c BarChartSeries) Values() NumberDataSource {
 	if c.x.Val == nil {
 		c.x.Val = crt.NewCT_NumDataSource()