test.js

        it('waits for delete to return before saving', function(done){
            // Given
            var options = {
                model: new Backbone.Model({
                    modules: new Backbone.Collection([
                        new Model(),
                        new Model()
                    ])
                }),
                success: function(){}
            };

            Model.prototype.save.restore();
            var saveSpy = sandbox.stub(Model.prototype, 'save', function(props, options){
                options.success(this);
            });

            syncher.del.restore();
            var delSpy = sandbox.stub(syncher, 'del', function(svc, data, options){
                if(svc.indexOf('variationModules') !== -1){
                    setTimeout(function(){
                        // Then
                        expect(delSpy).to.have.been.called;
                        expect(saveSpy).to.have.not.been.called;

                        options.success({ payload: { } });

                        // Then
                        done();

                    }, 1);
                }

                options.success({ payload: { } });
            });

            // When
            syncher.add(null, options);

        });