1var Fake = (function(){
 2  var fake = function(){
 3    _stubs = [];
 4    this.stub = function(method){
 5      if(_stubs[method] === undefined) {
 6        _stubs[method] = new Stub(this, method);
 7      }
 8      return _stubs[method];
 9    };
10  };
11  return function(){
12    return new fake();
13  };
14})();
15
16var Stub = (function(){
17  var stub = function(target, method){
18    this.arguments = [];
19    this.with = function(){
20      var args = new Arguments(this, target, method, arguments);
21      this.arguments.push(args);
22      return args;
23    };
24    this.andReturn = function(return_value){
25      target[method] = function(){
26        return return_value;
27      };
28    };
29    this.find_match_for = function(args){
30      for (var i = 0; i < this.arguments.length; i += 1) {
31        var matcher = this.arguments[i];
32        if(matcher.matches(args)){
33          return matcher;
34        }
35      }
36      throw "Matcher not found.";
37    };
38  };
39  return function(target, method){
40    return new stub(target, method);
41  };
42})();
43var Arguments = (function(){
44  var Arguments = function(stub, target, method, expected_args){
45    this.andReturn = function(return_value){
46      this.return_value = return_value;
47
48      target[method] = function(){
49        return stub.find_match_for(arguments).return_value;
50      };
51    };
52    this.matches = function(args){
53      var result = expected_args === args;
54      for (var i = 0; i < expected_args.length; i += 1) {
55        if(args[i] !== expected_args[i]){
56          return false;
57        }
58      }
59      return true;
60    };
61  };
62  return function(stub, target, method, expected_args){
63    return new Arguments(stub, target, method, expected_args);
64  };
65})();