javascript - Test the context of a method call using sinonjs -

I have a class where I initially compose a method -

 < Code> function MyClass () {this.onHttpCallback = _.bind (onHttpCallback, this); } function onHttpCallback () {// ...}   
 If call to  onHttpCallback , then always with reference to MyClass's object Is called?  
 I'm using sinon.js to counterfeit and the following code does not work -  
  it should be "bind", function () { // ctrl MyClass var dummy_obj = {}; var spy = sinon.spy (ctrl.onHttpCallback) is a purpose; spy.call (dummy_obj); spy.always callon (ctrl). should.be.ok;}); According to the comments in the following reply, it appears that it is impossible to test the bond for any method.   
  Update   
  Go to my problem   
  // Source.js function MyClass () {} MyClass.prototype.init = function () {this .onHttpCallback = _.bind (MyClass.onHttpCallback, this); } MyClass.onHttpCallback () {// ...} //Test.js (It should be bound to 'http callback', function) (sinon.spy (_, 'bind'); ctrl.init (); _ .bind .calledWith (ctrl.constructor.onHttpCallback, ctrl). should.be.ok; _.bind.restore ();});   
 Works like a charm!   
 
 
  this  change however you explicitly  MyClass , because you use the  call  with  dummy_obj  detective. 
 The detective wraps the original function, so there is no concept of binding that function in it. It will still accept different binding on the wrapper function, then try calling the original code from that  this , which is ignored by the original function.  
  var reference = {foo: 'bar'}; var origin = _.bind (function () {console.log (this);}, context); Var detective = function (original) {var spyFn = function () {var _this = this; spyFn.calledOn = function (ctx) {return ctx === _this; }; Original return (This, argument); }; Return detective FN; }; var originalSpy = Detective (Original); // will call spyFn with a different `this`, but the original binding will not affect originalSpy.call ({anything: 'else'}); & Gt; & Gt; {Foo: 'bar'} // Since the detective can not know the original binding, it seems that the assumption is wrong. OriginalSpy.calledOn (context) === Wrong;