Merging in #232. Allow destroy() to be called on non-persisted objects ... just in case.

backbone.js

@@ -304,10 +304,11 @@
       return (this.sync || Backbone.sync).call(this, method, this, options);
     },
 
-    // Destroy this model on the server. Upon success, the model is removed
+    // Destroy this model on the server if it was already persisted. Upon success, the model is removed
     // from its collection, if it has one.
     destroy : function(options) {
       options || (options = {});
+      if (this.isNew()) return this.trigger('destroy', this, this.collection, options);
       var model = this;
       var success = options.success;
       options.success = function(resp) {

test/collection.js

@@ -83,7 +83,7 @@ $(document).ready(function() {
     equals(otherCol.length, 1);
     equals(secondAdded, null);
     ok(opts.amazing);
-    
+
     var f = new Backbone.Model({id: 20, label : 'f'});
     var g = new Backbone.Model({id: 21, label : 'g'});
     var h = new Backbone.Model({id: 22, label : 'h'});
@@ -205,7 +205,7 @@ $(document).ready(function() {
     equals(counter, 2);
   });
 
-  test("Colllection: model destroy removes from all collections", function() {
+  test("Collection: model destroy removes from all collections", function() {
     var e = new Backbone.Model({id: 5, title: 'Othello'});
     e.sync = function(method, model, options) { options.success({}); };
     var colE = new Backbone.Collection([e]);
@@ -216,6 +216,17 @@ $(document).ready(function() {
     equals(null, e.collection);
   });
 
+  test("Colllection: non-persisted model destroy removes from all collections", function() {
+    var e = new Backbone.Model({title: 'Othello'});
+    e.sync = function(method, model, options) { throw "should not be called"; };
+    var colE = new Backbone.Collection([e]);
+    var colF = new Backbone.Collection([e]);
+    e.destroy();
+    ok(colE.length == 0);
+    ok(colF.length == 0);
+    equals(null, e.collection);
+  });
+
   test("Collection: fetch", function() {
     col.fetch();
     equals(lastRequest[0], 'read');

test/model.js

@@ -276,6 +276,13 @@ $(document).ready(function() {
     ok(_.isEqual(lastRequest[1], doc));
   });
 
+  test("Model: non-persisted destroy", function() {
+    attrs = { 'foo': 1, 'bar': 2, 'baz': 3};
+    a = new Backbone.Model(attrs);
+    a.sync = function() { throw "should not be called"; };
+    ok(a.destroy(), "non-persisted model should not call sync");
+  });
+
   test("Model: validate", function() {
     var lastError;
     var model = new Backbone.Model();