在 Jasmine 中监视 JQuery 选择器 [英] Spying on JQuery Selectors in Jasmine
问题描述
我正在使用 Jasmine 对一些 JavaScript 进行单元测试,并希望监视(模拟)由 jQuery 选择器访问的 DOM 元素.
I am unit testing some JavaScript with Jasmine and wish to spy on (mock) an element of the DOM that is accessed by a jQuery selector.
我的规格是:
it("should be able to mock DOM call", function() {
spyOn($("#Something"), 'val').andReturn("bar");
result = $("#Something").val();
expect(result).toEqual("bar");
});
在我的 specrunner.html 中,我有:
In my specrunner.html I have:
<input type="hidden" id="Something" value="foo" />
不幸的是规范失败了:
应该能够模拟 DOM 调用 Expected 'foo' 等于 'bar'.
should be able to mock DOM call Expected 'foo' to equal 'bar'.
推荐答案
这行错误:
spyOn($("#Something"), 'val').andReturn("bar");
Jasmine 的 spyOn 函数需要两个参数.第一个是现有对象.第二个是作为字符串的函数名称.您正确地将函数名称作为字符串 ("val") 传递,但没有将现有对象作为第一个参数传递.
Jasmine's spyOn function expects two parameters. The first is an existing object. The second is a function name as a string. You are correctly passing in the function name as a string ("val") but you are not passing in an existing object as the first parameter.
$("#Something")
...不是现有对象.它是 jQuery 选择器的结果(返回值).更具体地说,它将返回一个表示匹配节点的 jQuery 对象 - 有点像结果数组.
...is not an existing object. It is the result (the return value) of a jQuery selector. More specifically, it will return a jQuery object representing the matched nodes - kind of like an array of results.
$
...是一个现有的对象.
...is an existing object.
$.fn
...是一个现有的对象.
...is an existing object.
$("#Something")
...不是一个现有的对象 - 它是jQuery选择器的结果.
...is not an existing object - it is the result of a jQuery selector.
这会起作用:
it("should be able to mock DOM call", function () {
//spyOn($.fn, "val").andReturn("bar"); //pre-jasmine 2.0 syntax
spyOn($.fn, "val").and.returnValue("bar"); //Jasmine 2.0 Syntax
var result = $("#Something").val();
expect(result).toEqual("bar");
});
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