fix(singlestat): fix bug in threshold calculations

public/app/plugins/panel/singlestat/module.ts

@@ -221,7 +221,7 @@ function singleStatPanel($location, linkSrv, $timeout, templateSrv) {
 
 function getColorForValue(data, value) {
   for (var i = data.thresholds.length; i > 0; i--) {
-    if (value >= data.thresholds[i]) {
+    if (value >= data.thresholds[i-1]) {
       return data.colorMap[i];
     }
   }

public/app/plugins/panel/singlestat/specs/singlestat_panel_spec.ts

@@ -2,12 +2,12 @@ import {describe, beforeEach, it, sinon, expect} from 'test/lib/common';
 
 import {getColorForValue} from '../module';
 
-describe('grafanaSingleStat', function() {
+describe.only('grafanaSingleStat', function() {
   describe('legacy thresholds', () => {
     describe('positive thresholds', () => {
       var data: any = {
         colorMap: ['green', 'yellow', 'red'],
-        thresholds: [0, 20, 50]
+        thresholds: [20, 50]
       };
 
       it('5 should return green', () => {
@@ -29,7 +29,7 @@ describe('grafanaSingleStat', function() {
   describe('negative thresholds', () => {
     var data: any = {
       colorMap: ['green', 'yellow', 'red'],
-      thresholds: [ -20, 0, 20]
+      thresholds: [ 0, 20]
     };
 
     it('-30 should return green', () => {
@@ -48,7 +48,7 @@ describe('grafanaSingleStat', function() {
   describe('negative thresholds', () => {
     var data: any = {
       colorMap: ['green', 'yellow', 'red'],
-      thresholds: [ -40, -27, 20]
+      thresholds: [-27, 20]
     };
 
     it('-30 should return green', () => {