javascript 在 angularjs 中对异步服务进行单元测试
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Unit testing an asynchronous service in angularjs
提问by Hidden Developer
I am trying to unit test a service which has asynchronous methods but am having no luck.
我正在尝试对具有异步方法但没有运气的服务进行单元测试。
I have tried to implement with promises by using the $q support in angularjs.
我试图通过使用 angularjs 中的 $q 支持来实现承诺。
Any help would be appreciated.
任何帮助，将不胜感激。
angular.module('myapp', ['myservice']);
angular.module('myservice', []).factory('myservice', function($q) {
var ls = {};
ls.DoIt = function() {
var deferred = $q.defer();
setTimeout(function(){
deferred.resolve(5);
},3000);
return deferred.promise;
}
return ls;
});
describe('services', function () {
beforeEach(module('myservice'));
it("should equal 2", inject(function(myservice) {
myservice.DoIt().then(function(returned) {
expect(returned).toEqual(2);
});
}));
});
回答by pkozlowski.opensource
First of all, the setTimeoutis particularly tricky to test since it hard to mock. Fortunately AngularJS has a wrapper around it ($timeout) that plays the same role but can be easily mocked:
首先，setTimeout由于难以模拟，所以测试特别棘手。幸运的是 AngularJS 有一个包装器 ( $timeout) ，它扮演着同样的角色，但很容易被嘲笑：
ls.DoIt = function() {
var deferred = $q.defer();
$timeout(function(){
deferred.resolve(5);
},3000);
return deferred.promise;
}
The mock provided for $timeoutallows us to easily simulate elapsed time (with $timeout.flush()) which means our tests can run fast, without really waiting for the async event to complete (please note that the production code is still using async API!).
提供的模拟$timeout允许我们轻松模拟经过的时间（使用$timeout.flush()），这意味着我们的测试可以快速运行，而无需真正等待异步事件完成（请注意，生产代码仍在使用异步 API！）。
The changed tests would look like:
更改后的测试如下所示：
it("should equal 5", inject(function(myservice, $timeout) {
var valueToVerify;
myservice.DoIt().then(function(returned) {
valueToVerify = returned;
});
$timeout.flush();
expect(valueToVerify).toEqual(5);
}));
And finally the working jsFiddle: http://jsfiddle.net/v9L9G/1/
最后是工作 jsFiddle：http: //jsfiddle.net/v9L9G/1/
回答by Caio Cunha
It's not related to Angular itself, but to Jasmine async tests.
它与 Angular 本身无关，而是与Jasmine 异步测试相关。
If you need a setTimeoutuse Angular $timeout. And if you wish to have a fine control over setTimeout/$timeout executions, use mocked Clock.
如果您需要setTimeout使用 Angular $timeout。如果您希望对 setTimeout/$timeout 执行进行精细控制，请使用模拟 Clock。
