Move open-failed error message to the handler, adjust test for the new message style. Add 'numberOfHandlers()' method for events.

src/eventsource.js

@@ -122,6 +122,18 @@ $.EventSource.prototype = {
         }
     },
 
+    /**
+     * Get the amount of handlers registered for a given event.
+     * @param {String} eventName - Name of event to inspect.
+     * @return {number} amount of events
+     */
+    numberOfHandlers: function (eventName) {
+        var events = this.events[ eventName ];
+        if ( !events ) {
+            return 0;
+        }
+        return events.length;
+    },
 
     /**
      * Remove all event handlers for a given event type. If no type is given all

src/tilesource.js

@@ -529,7 +529,7 @@ $.TileSource.prototype = {
                         exception rather than the second one raised when we try to access xhr.status
                      */
                     try {
-                        msg = "HTTP " + xhr.status + " attempting to load TileSource";
+                        msg = "HTTP " + xhr.status + " attempting to load TileSource: " + url;
                     } catch ( e ) {
                         var formattedExc;
                         if ( typeof ( exc ) === "undefined" || !exc.toString ) {
@@ -538,9 +538,11 @@ $.TileSource.prototype = {
                             formattedExc = exc.toString();
                         }
 
-                        msg = formattedExc + " attempting to load TileSource";
+                        msg = formattedExc + " attempting to load TileSource: " + url;
                     }
 
+                    $.console.error(msg);
+
                     /***
                      * Raised when an error occurs loading a TileSource.
                      *

test/modules/basic.js

@@ -58,8 +58,8 @@
 
             assert.equal($(".openseadragon-message").length, 1, "Open failures should display a message");
 
-            assert.ok(testLog.error.contains('["AJAX request returned %d: %s",404,"/test/data/not-a-real-file"]'),
-               "AJAX failures should be logged to the console");
+            assert.ok(testLog.error.contains('["HTTP 404 attempting to load TileSource: /test/data/not-a-real-file"]'),
+                "'open-failed' fired after AJAX error handler prints error to the console.'");
 
             done();
         });

test/modules/events.js

@@ -1152,6 +1152,36 @@
     });
 
     // ----------
+    QUnit.test( 'Viewer: event count test with \'tile-drawing\'', function (assert) {
+        var done = assert.async();
+        assert.ok(viewer.numberOfHandlers('tile-drawing') === 0,
+            "'tile-drawing' event is empty by default.");
+
+        var tileDrawing = function ( event ) {
+            viewer.removeHandler( 'tile-drawing', tileDrawing );
+            assert.ok(viewer.numberOfHandlers('tile-drawing') === 0,
+                "'tile-drawing' deleted: count is 0.");
+            viewer.close();
+            done();
+        };
+
+        var tileDrawingDummy = function ( event ) {};
+
+        viewer.addHandler( 'tile-drawing', tileDrawing );
+        assert.ok(viewer.numberOfHandlers('tile-drawing') === 1,
+            "'tile-drawing' event set to 1.");
+
+        viewer.addHandler( 'tile-drawing', tileDrawingDummy );
+        assert.ok(viewer.numberOfHandlers('tile-drawing') === 2,
+            "'tile-drawing' event set to 2.");
+
+        viewer.removeHandler( 'tile-drawing', tileDrawingDummy );
+        assert.ok(viewer.numberOfHandlers('tile-drawing') === 1,
+            "'tile-drawing' deleted once: count is 1.");
+
+        viewer.open( '/test/data/testpattern.dzi' );
+    } );
+
     QUnit.test( 'Viewer: tile-drawing event', function (assert) {
         var done = assert.async();
         var tileDrawing = function ( event ) {