test observer

test_observer.js

describe('design pattern', function () {
    var testData = null;
    it('observer', function(){
        var Observer = function(){
            this.subscribers = [];
        };
        Observer.prototype = {
            publish: function(data){
                var i = 0,
                    len = this.subscribers.length;
                for(; i<len; i++){
                    this.subscribers[i](data);
                }
            },
            subscribe: function(callback){
                this.subscribers.push(callback);
            }
        };
        var observer = new Observer();
        var registry = function(data){
            testData = data;
        };

        observer.subscribe(registry);
        observer.publish("end");

        expect(testData).not.toBe(null);
    });
});