Added ImageOveray Error handling.

spec/Layers/RasterLayerSpec.js

@@ -6,4 +6,91 @@ describe('L.esri.RasterLayer', function () {
     layer._currentImage = null;
     expect(function () { layer.setOpacity(0.5); }).to.not.throw();
   });
+
+  // Extend 'abstract' RasterLayer object and implement functionality required for tests
+  var TestRasterLayer = L.esri.RasterLayer.extend({
+    initialize: function (options) {
+      this.service = {
+        metadata: function () {}
+      };
+    },
+
+    _buildExportParams: function () {
+      return 'data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=='; // A blank image URL
+    },
+
+    _requestExport: function (uri, bounds) {
+      this._renderImage(uri, bounds);
+    }
+  });
+
+  describe('_renderImage', function () {
+    var div, map, layer;
+
+    // Set up things before each test run
+    beforeEach(function () {
+      div = document.createElement('div');
+      div.style.width = '800px';
+      div.style.height = '600px';
+      div.style.visibility = 'hidden';
+
+      document.body.appendChild(div);
+      map = new L.Map(div);
+      map.setView([0, 0], 1);  // view needs to be set so when layer is added it is initilized
+
+      map.addLayer = sinon.spy(map.addLayer);         // we want to spy layers being added and removed from the map
+      map.removeLayer = sinon.spy(map.removeLayer);
+
+      layer = new TestRasterLayer();
+    });
+
+    // Clean up after each test run
+    afterEach(function () {
+      document.body.removeChild(div);
+    });
+
+    describe('when error is raised when loading the ImageOverlay', function () {
+      it('should raise an error', function () {
+        var errorCallback = sinon.spy();
+        layer.on('error', errorCallback);
+
+        layer.addTo(map);
+
+        var imageOverlay = map.addLayer.getCall(1).args[0]; // Get the ImageOverlay which is being added to the map
+        imageOverlay.fire('error');                         // And fire the error event on the layer
+
+        expect(errorCallback.called).to.be.true;
+      });
+
+      it('should remove the ImageOverlay which is being loaded', function () {
+        layer.addTo(map);
+
+        var imageOverlay = map.addLayer.getCall(1).args[0];
+        imageOverlay.fire('error');
+
+        expect(map.removeLayer.calledWith(imageOverlay)).to.be.true;
+      });
+
+      it('should stop listening for the load event', function () {
+        layer.addTo(map);
+
+        var imageOverlay = map.addLayer.getCall(1).args[0];
+        imageOverlay.off = sinon.spy(imageOverlay.off);
+        imageOverlay.fire('error');
+
+        expect(imageOverlay.off.calledWith('load', sinon.match.func, layer)).to.be.true;
+      });
+    });
+
+    describe('when the ImageOverlay has loaded', function () {
+      it('should stop listening for the error event', function () {
+        layer.addTo(map);
+        var imageOverlay = map.addLayer.getCall(1).args[0];
+        imageOverlay.off = sinon.spy(imageOverlay.off);
+        imageOverlay.fire('load');
+
+        expect(imageOverlay.off.calledWith('error', sinon.match.func, layer)).to.be.true;
+      });
+    });
+  });
 });

src/Layers/RasterLayer.js

@@ -170,8 +170,14 @@ export var RasterLayer = Layer.extend({
         interactive: this.options.interactive
       }).addTo(this._map);
 
-      // once the image loads
-      image.once('load', function (e) {
+      var onOverlayError = function () {
+        this._map.removeLayer(image);
+        this.fire('error');
+        image.off('load', onOverlayLoad, this);
+      };
+
+      var onOverlayLoad = function (e) {
+        image.off('error', onOverlayLoad, this);
         if (this._map) {
           var newImage = e.target;
           var oldImage = this._currentImage;
@@ -210,7 +216,13 @@ export var RasterLayer = Layer.extend({
         this.fire('load', {
           bounds: bounds
         });
-      }, this);
+      };
+
+      // If loading the image fails
+      image.once('error', onOverlayError, this);
+
+      // once the image loads
+      image.once('load', onOverlayLoad, this);
 
       this.fire('loading', {
         bounds: bounds