diff --git a/src/ol/map.js b/src/ol/map.js
index 13c5efccbf..bcfa364b5b 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -1118,10 +1118,8 @@ ol.Map.prototype.handleLayerGroupPropertyChanged_ = function(event) {
  */
 ol.Map.prototype.handleLayerGroupChanged_ = function() {
   if (!goog.isNull(this.layerGroupPropertyListenerKeys_)) {
-    var length = this.layerGroupPropertyListenerKeys_.length;
-    for (var i = 0; i < length; ++i) {
-      goog.events.unlistenByKey(this.layerGroupPropertyListenerKeys_[i]);
-    }
+    goog.array.forEach(this.layerGroupPropertyListenerKeys_,
+        goog.events.unlistenByKey);
     this.layerGroupPropertyListenerKeys_ = null;
   }
   var layerGroup = this.getLayerGroup();
diff --git a/test/spec/ol/source/bingmapssource.test.js b/test/spec/ol/source/bingmapssource.test.js
index 3abe87976d..a53a9f63a1 100644
--- a/test/spec/ol/source/bingmapssource.test.js
+++ b/test/spec/ol/source/bingmapssource.test.js
@@ -27,7 +27,7 @@ describe('ol.source.BingMaps', function() {
       goog.net.Jsonp = googNetJsonp;
       var key = source.on('change', function() {
         if (source.getState() === 'ready') {
-          source.unByKey(key);
+          ol.Observable.unByKey(key);
           tileGrid = source.getTileGrid();
           done();
         }
@@ -79,3 +79,4 @@ describe('ol.source.BingMaps', function() {
 goog.require('goog.net.Jsonp');
 goog.require('ol.source.BingMaps');
 goog.require('ol.tilecoord');
+goog.require('ol.Observable');
diff --git a/test/spec/ol/source/tilejsonsource.test.js b/test/spec/ol/source/tilejsonsource.test.js
index b65b120298..68ee73caa2 100644
--- a/test/spec/ol/source/tilejsonsource.test.js
+++ b/test/spec/ol/source/tilejsonsource.test.js
@@ -40,7 +40,7 @@ describe('ol.source.TileJSON', function() {
       goog.net.Jsonp = googNetJsonp;
       var key = source.on('change', function() {
         if (source.getState() === 'ready') {
-          source.unByKey(key);
+          ol.Observable.unByKey(key);
           tileGrid = source.getTileGrid();
           done();
         }
@@ -91,3 +91,4 @@ goog.require('goog.events');
 goog.require('goog.net.Jsonp');
 goog.require('ol.source.State');
 goog.require('ol.source.TileJSON');
+goog.require('ol.Observable');