Fix and add unit tests.

src/tilecache.js

@@ -223,7 +223,7 @@ $.TileCache.prototype = /** @lends OpenSeadragon.TileCache.prototype */{
         for ( var i = 0; i < this._tilesLoaded.length; ++i ) {
             tileRecord = this._tilesLoaded[ i ];
             if ( tileRecord.tiledImage === tiledImage ) {
-                this._unloadTile(tileRecord.tile);
+                this._unloadTile(tileRecord);
                 this._tilesLoaded.splice( i, 1 );
                 i--;
             }

test/modules/events.js

@@ -1040,4 +1040,31 @@
         viewer.open( '/test/data/testpattern.dzi' );
     } );
 
+    asyncTest( 'Viewer: tile-unloaded event.', function() {
+        var tiledImage;
+        var tile;
+
+        function tileLoaded( event ) {
+            viewer.removeHandler( 'tile-loaded', tileLoaded);
+            tiledImage = event.tiledImage;
+            tile = event.tile;
+            setTimeout(function() {
+                tiledImage.reset();
+            }, 0);
+        }
+
+        function tileUnloaded( event ) {
+            viewer.removeHandler( 'tile-unloaded', tileUnloaded );
+            equal( tile, event.tile,
+                "The unloaded tile should be the same than the loaded one." );
+            equal( tiledImage, event.tiledImage,
+                "The tiledImage of the unloaded tile should be the same than the one of the loaded one." );
+            start();
+        }
+
+        viewer.addHandler( 'tile-loaded', tileLoaded );
+        viewer.addHandler( 'tile-unloaded', tileUnloaded );
+        viewer.open( '/test/data/testpattern.dzi' );
+    } );
+
 } )();

test/modules/tilecache.js

@@ -13,8 +13,15 @@
 
     // ----------
     asyncTest('basics', function() {
-        var fakeTiledImage0 = {};
+        var fakeViewer = {
-        var fakeTiledImage1 = {};
+            raiseEvent: function() {}
+        };
+        var fakeTiledImage0 = {
+            viewer: fakeViewer
+        };
+        var fakeTiledImage1 = {
+            viewer: fakeViewer
+        };
 
         var fakeTile0 = {
             url: 'foo.jpg',
@@ -58,7 +65,12 @@
 
     // ----------
     asyncTest('maxImageCacheCount', function() {
-        var fakeTiledImage0 = {};
+        var fakeViewer = {
+            raiseEvent: function() {}
+        };
+        var fakeTiledImage0 = {
+            viewer: fakeViewer
+        };
 
         var fakeTile0 = {
             url: 'different.jpg',