模拟和测试Mocha，Chai和Sinon的按键事件？

Question

I have a Backbone view that has custom events for keyup and keydown events.

events: {
    "keyup .search-box": "changeTextTimer",
    "keydown .search-box": "cancelTextTimer"
},

I'm writing unit tests to check if those callbacks are getting invoked after a keyup or keydown. I use jQuery to trigger the key event.

it("should call cancelTextTimer", function() {
    var searchBox = new SearchBoxView({el: $(HTML),}).render();

    var e = $.Event("keydown");
    e.which = 65;
    searchBox.$(".search-box").trigger(e);

    var changeTextTimer = sinon.spy(searchBox, "cancelTextTimer");
    _.defer(changeTextTimer.restore);

    changeTextTimer.should.have.been.calledOnce;

});

However, I receive a

AssertionError: expected cancelTextTimer to have been called exactly once, but 
it was called 0 times: Got value cancelTextTimer but expected a value undefined undefined

Answer 1

Try this

it("should call cancelTextTimer", function(done) {
    var searchBox = new SearchBoxView({el: $(HTML),}).render();
    var changeTextTimer = sinon.spy(searchBox, "cancelTextTimer");
    _.defer(changeTextTimer.restore);

    var e = $.Event("keydown");
    e.which = 65;
    searchBox.$(".search-box").trigger(e);

    setTimeout(() => {
        changeTextTimer.should.have.been.calledOnce;
        done();
    }, 0);

});