[英]Stubbing and/or spying on an optional global function: Sinon, mocha & chai
I have a method that checks whether or not a global function is defined (it may or may not be available, depends on each client's request).我有一个方法可以检查是否定义了全局函数(它可能可用也可能不可用,取决于每个客户的请求)。 If it is defined, it will call it with the appropriate data.如果已定义,它将使用适当的数据调用它。 If not, it will fail silently.如果没有,它将静默失败。 That's the desired behavior.这就是期望的行为。
What I want to do is test it.我想做的是测试它。 Is there a way to mock and/or spy on libFunction
so that I can ensure it's being called once with the correct data (the function here is very much simplified, there's some data processing that happens along the way).有没有办法模拟和/或监视libFunction
以便我可以确保使用正确的数据调用一次它(这里的函数非常简化,沿途会发生一些数据处理)。
Here's the method in question:这是有问题的方法:
function sendData(data) {
let exists;
try {
// eslint-disable-next-line no-undef
if (libFunction) exists = true;
} catch (e) {
exists = false;
}
if (exists) {
// eslint-disable-next-line no-undef
libFunction(data);
}
}
I've tried defining libFunction
in my tests and then stubbing that, but that doesn't do what I want:我已经尝试在我的测试中定义libFunction
然后对其进行存根,但这并没有达到我想要的效果:
describe('sendEvent', function () {
function libFunction(data) {
console.log('hi', data);
}
it('should call libFunction once', function () {
var stub = sinon.stub(libFunction);
var data = "testing";
sendEvent(data);
expect(stub.called).to.be.true;
});
});
This test does not pass, however: AssertionError: expected undefined to be true
但是,此测试未通过: AssertionError: expected undefined to be true
I've tried something similar with a spy:我用间谍尝试过类似的事情:
describe('sendEvent', function () {
function libFunction(data) {
console.log('hi', data);
}
it('should call libFunction once', function () {
var spy = sinon.spy(libFunction);
var data = "testing";
sendEvent(data);
expect(spy.called).to.be.true;
});
});
This also fails: AssertionError: expected false to be true
这也失败了: AssertionError: expected false to be true
Is there a way to do this?有没有办法做到这一点?
FWIW, I came across this question while trying to solve an issue for stubbing a global method in Node. FWIW,我在尝试解决在 Node.js 中存根全局方法的问题时遇到了这个问题。 In my case, this worked (my example uses Sinon.sandbox
, but "regular" Sinon.spy
should work, as well):就我而言,这是有效的(我的示例使用Sinon.sandbox
,但“常规” Sinon.spy
应该有效):
const encodeSpy = sandbox.spy(global, "encodeURIComponent");
// later...
Sinon.assert.calledWith(encodeSpy, {expectedParamValue});
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