Javascript 如何为 Jasmine 间谍的多次调用提供不同的返回值
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/26898613/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to have different return values for multiple calls on a Jasmine spy
提问by mikhail
Say I'm spying on a method like this:
假设我正在监视这样的方法：
spyOn(util, "foo").andReturn(true);
The function under test calls util.foomultiple times.
被测函数util.foo多次调用。
Is it possible to have the spy return truethe first time it's called, but return falsethe second time? Or is there a different way to go about this?
是否有可能让间谍true在第一次被调用时返回，但false第二次返回？或者有什么不同的方法来解决这个问题？
回答by Ocean
You can use spy.and.returnValues(as Jasmine 2.4).
您可以使用spy.and.returnValues（如 Jasmine 2.4）。
for example
例如
describe("A spy, when configured to fake a series of return values", function() {
beforeEach(function() {
spyOn(util, "foo").and.returnValues(true, false);
});
it("when called multiple times returns the requested values in order", function() {
expect(util.foo()).toBeTruthy();
expect(util.foo()).toBeFalsy();
expect(util.foo()).toBeUndefined();
});
});There is some thing you must be careful about, there is another function will similar spell returnValuewithout s, if you use that, jasmine will not warn you.
有一些事情你必须小心，还有另一个功能会returnValue没有类似的咒语s，如果你使用它，茉莉花不会警告你。
回答by voithos
For older versions of Jasmine, you can use spy.andCallFakefor Jasmine 1.3 or spy.and.callFakefor Jasmine 2.0, and you'll have to keep track of the 'called' state, either through a simple closure, or object property, etc.
对于较旧版本的 Jasmine，您可以使用spy.andCallFakeJasmine 1.3 或spy.and.callFakeJasmine 2.0，并且您必须通过简单的闭包或对象属性等来跟踪“被调用”状态。
var alreadyCalled = false;
spyOn(util, "foo").andCallFake(function() {
if (alreadyCalled) return false;
alreadyCalled = true;
return true;
});
回答by Dabrule
If you wish to write a spec for each call you can also use beforeAll instead of beforeEach :
如果您想为每个调用编写规范，您还可以使用 beforeAll 而不是 beforeEach ：
describe("A spy taking a different value in each spec", function() {
beforeAll(function() {
spyOn(util, "foo").and.returnValues(true, false);
});
it("should be true in the first spec", function() {
expect(util.foo()).toBeTruthy();
});
it("should be false in the second", function() {
expect(util.foo()).toBeFalsy();
});
});
