在QUnit测试中为$（this）设置范围

Question

How do you setup correct scoping in a QUnit test environment for testing callback functions?

Code to test:

<script type="text/javascript">
    APP = {};
    APP.callBack = function() {
        $(this).closest("input").val('foobar');
    };

    $(function() {
        $("#button").click(APP.callBack);
    });
</script>
<div>
  <a id="button" href="#"></a>
  <input id="id-for-testing-only" name="test" type="text" value="barfoo" />
</div>

Test code:

test("try callback with 'this' scope", function() {
    APP.callBack();
    equals($("#id-for-testing-only").val(), "foobar", "should set value to 'foobar'");
});

Answer 1

我想，你可能需要使用.trigger()来触发“点击”按钮，然后检查值，而不是直接调用回调函数，它不会作用域按钮的this时候独立地调用。

$("#button").trigger("click");

Answer 2

I don't know about in QUnit, but in Javascript in general you do it like this:

func.apply((this), [arguments]);

for example

function foo(x) { return this + x; }

foo.apply(1, [2]) == 3

so I would try

APP.callback.apply(whateverYouWantForThis);