Sinon Spy not working with Javascript call or apply

问题

I'm trying to use sinon.spy to check if the play function is being called for a component. The problem is that the spy counter is not updating, even though I've confirmed that my component's function is indeed being called.

I've tracked it down to the use of Javascript's call function:

handleDone: function(e) {
  for (var i = 0; i < this.components.length; i++) {
    if (this.components[i].element === e.target) {
      if (this.components[i].hasOwnProperty("play")) {
        // This won't trigger the spy.
        this.components[i]["play"].call(this.components[i].element);
      }
      break;
    }
  }
}

A similar thing happens when swapping call for apply.

[UPDATED] Here is the relevant test:

var page = document.getElementById("page"),
  demo = document.getElementById("demo"),
  playSpy;

suiteSetup(function() {
  playSpy = sinon.spy(demo, "play");
});

suiteTeardown(function() {
  demo.play.restore();
});

suite("done", function() {
  test("rise-component-done fired from element with play property", function() {
    assert(playSpy.notCalled);  //true
    demo.sendDone();
    assert(playSpy.calledOnce); //false
  });
});

And the play and sendDone functions in the demo component:

play: function() {
  console.log("play");
},

sendDone: function() {
  this.dispatchEvent(new CustomEvent("rise-component-done", { "bubbles": true }));
}

The page component is registered to listen for this event:

this.addEventListener("rise-component-done", this.handleDone);

Anyone know of a workaround?

Thx.

回答1:

So the problem wasn't actually related to the call method at all as Ben illustrated. After much tinkering, I realized I had to change this line:

playSpy = sinon.spy(demo, "play");

to this:

playSpy = sinon.spy(page.components[0], "play");

Now my tests pass. Hooray! I just wish it hadn't taken me the better part of a day to debug.

来源：https://stackoverflow.com/questions/29370799/sinon-spy-not-working-with-javascript-call-or-apply

标签

javascript

unit-testing

sinon