Modify VolumeZonePredicate to handle multi-zone PV

Modifies the VolumeZonePredicate to handle a PV that belongs to more
then one zone or region. This is indicated by the zone or region label
value containing a comma separated list.

pkg/volume/util/util_test.go

@@ -23,6 +23,7 @@ import (
 
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
 	// util.go uses api.Codecs.LegacyCodec so import this package to do some
 	// resource initialization.
 	_ "k8s.io/kubernetes/pkg/api/install"
@@ -229,3 +230,36 @@ spec:
 		}
 	}
 }
+func TestZonesToSet(t *testing.T) {
+	functionUnderTest := "ZonesToSet"
+	// First part: want an error
+	sliceOfZones := []string{"", ",", "us-east-1a, , us-east-1d", ", us-west-1b", "us-west-2b,"}
+	for _, zones := range sliceOfZones {
+		if got, err := ZonesToSet(zones); err == nil {
+			t.Errorf("%v(%v) returned (%v), want (%v)", functionUnderTest, zones, got, "an error")
+		}
+	}
+
+	// Second part: want no error
+	tests := []struct {
+		zones string
+		want  sets.String
+	}{
+		{
+			zones: "us-east-1a",
+			want:  sets.String{"us-east-1a": sets.Empty{}},
+		},
+		{
+			zones: "us-east-1a, us-west-2a",
+			want: sets.String{
+				"us-east-1a": sets.Empty{},
+				"us-west-2a": sets.Empty{},
+			},
+		},
+	}
+	for _, tt := range tests {
+		if got, err := ZonesToSet(tt.zones); err != nil || !got.Equal(tt.want) {
+			t.Errorf("%v(%v) returned (%v), want (%v)", functionUnderTest, tt.zones, got, tt.want)
+		}
+	}
+}