Return nothing from previously set bounds

Previously, if bounds were not set, the default value that would be
returned was ["0", "0"], which is incorrect. This now returns [] when
there was nothing set for a particular axis.

bolt/internal/internal.go

@@ -2,7 +2,6 @@ package internal
 
 import (
 	"encoding/json"
-	"strconv"
 
 	"github.com/gogo/protobuf/proto"
 	"github.com/influxdata/chronograf"
@@ -268,16 +267,15 @@ func UnmarshalDashboard(data []byte, d *chronograf.Dashboard) error {
 
 		axes := make(map[string]chronograf.Axis, len(c.Axes))
 		for a, r := range c.Axes {
-			axis := chronograf.Axis{}
-			// repair legacy bounds
-			for _, bound := range r.LegacyBounds {
-				axis.Bounds = append(axis.Bounds, strconv.FormatInt(bound, 10))
+			if r.Bounds != nil {
+				axes[a] = chronograf.Axis{
+					Bounds: r.Bounds,
+				}
+			} else {
+				axes[a] = chronograf.Axis{
+					Bounds: []string{},
+				}
 			}
-
-			if len(r.Bounds) > 0 {
-				axis.Bounds = r.Bounds
-			}
-			axes[a] = axis
 		}
 
 		cells[i] = chronograf.DashboardCell{

bolt/internal/internal_test.go

@@ -201,7 +201,80 @@ func Test_MarshalDashboard_WithLegacyBounds(t *testing.T) {
 				},
 				Axes: map[string]chronograf.Axis{
 					"y": chronograf.Axis{
-						Bounds: []string{"0", "5"},
+						Bounds: []string{},
+					},
+				},
+				Type: "line",
+			},
+		},
+		Templates: []chronograf.Template{},
+		Name:      "Dashboard",
+	}
+
+	var actual chronograf.Dashboard
+	if buf, err := internal.MarshalDashboard(dashboard); err != nil {
+		t.Fatal("Error marshaling dashboard: err", err)
+	} else if err := internal.UnmarshalDashboard(buf, &actual); err != nil {
+		t.Fatal("Error unmarshaling dashboard: err:", err)
+	} else if !cmp.Equal(expected, actual) {
+		t.Fatalf("Dashboard protobuf copy error: diff follows:\n%s", cmp.Diff(expected, actual))
+	}
+}
+
+func Test_MarshalDashboard_WithNoLegacyBounds(t *testing.T) {
+	dashboard := chronograf.Dashboard{
+		ID: 1,
+		Cells: []chronograf.DashboardCell{
+			{
+				ID:   "9b5367de-c552-4322-a9e8-7f384cbd235c",
+				X:    0,
+				Y:    0,
+				W:    4,
+				H:    4,
+				Name: "Super awesome query",
+				Queries: []chronograf.DashboardQuery{
+					{
+						Command: "select * from cpu",
+						Label:   "CPU Utilization",
+						Range: &chronograf.Range{
+							Upper: int64(100),
+						},
+					},
+				},
+				Axes: map[string]chronograf.Axis{
+					"y": chronograf.Axis{
+						LegacyBounds: [2]int64{},
+					},
+				},
+				Type: "line",
+			},
+		},
+		Templates: []chronograf.Template{},
+		Name:      "Dashboard",
+	}
+
+	expected := chronograf.Dashboard{
+		ID: 1,
+		Cells: []chronograf.DashboardCell{
+			{
+				ID:   "9b5367de-c552-4322-a9e8-7f384cbd235c",
+				X:    0,
+				Y:    0,
+				W:    4,
+				H:    4,
+				Name: "Super awesome query",
+				Queries: []chronograf.DashboardQuery{
+					{
+						Command: "select * from cpu",
+						Label:   "CPU Utilization",
+						Range: &chronograf.Range{
+							Upper: int64(100),
+						},
+					},
+				},
+				Axes: map[string]chronograf.Axis{
+					"y": chronograf.Axis{
+						Bounds: []string{},
 					},
 				},
 				Type: "line",