为什么我在Jasmine 1.3.x中的AngularJS异步测试无法正常工作？

Question

Hi I have a feature complete web-app written using AngularJS (1.5.11) and now I'm getting started with unit testing using karma (0.12.37), grunt-karma (0.8.3), karma-chrome-launcher (0.1.12), karma-phantomjs-launcher (1.0.4), phantomjs-prebuilt (2.1.14), jasmine-promise-matchers (2.3.0) and karma-jasmine (0.1.6), with a 1.3.x Jasmine version.

I'm not very confident in testing asynchronous stuff, so I started googling around and I always end up seeing the only mandatory thing to run AngularJS async tests is a $rootScope/$scope.$apply/$digest right after the async function has been called.

Eventually I found someone suggesting me to use runs() and waitsFor() and the test in this plunkr in particular runs smoothly when using the chrome-launcher but fails when using phantomjs-launcher, throwing an error like the following:

Expected { myError : { error : 'error_message' }, line : <factory's line of code which throws the error>, sourceURL : 'path/to/factory.js', stack :

     <function throwing error> B@path/to/factory.js:<factory's line of code which throws the error>
     <"async" function> A@path/to/factory.js:<factory's line of code which calls B()>
     path/to/factory-spec.js:<the following line of code: var promise = HandleService.A();>
     invoke@path/to/angular/angular.js:4771:24
     WorkFn@path/to/angular-mocks/angular-mocks.js:3130:26
     execute@path/to/node_modules/karma-jasmine/lib/jasmine.js:1145:22
     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2177:38
     start@path/to/node_modules/karma-jasmine/lib/jasmine.js:2130:13
     execute@path/to/node_modules/karma-jasmine/lib/jasmine.js:2458:19
     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2177:38
     start@path/to/node_modules/karma-jasmine/lib/jasmine.js:2130:13
     execute@path/to/node_modules/karma-jasmine/lib/jasmine.js:2604:19
     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2177:38
     start@path/to/node_modules/karma-jasmine/lib/jasmine.js:2130:13
     execute@path/to/node_modules/karma-jasmine/lib/jasmine.js:2604:19
     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2177:38
     onComplete@path/to/node_modules/karma-jasmine/lib/jasmine.js:2173:23
     finish@path/to/node_modules/karma-jasmine/lib/jasmine.js:2561:15
     path/to/node_modules/karma-jasmine/lib/jasmine.js:2605:16

     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2187:24
     onComplete@path/to/node_modules/karma-jasmine/lib/jasmine.js:2173:23
     finish@path/to/node_modules/karma-jasmine/lib/jasmine.js:2561:15
     path/to/node_modules/karma-jasmine/lib/jasmine.js:2605:16

     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2187:24
     onComplete@path/to/node_modules/karma-jasmine/lib/jasmine.js:2173:23
     finish@path/to/node_modules/karma-jasmine/lib/jasmine.js:2432:15
     path/to/node_modules/karma-jasmine/lib/jasmine.js:2459:16

     next_@path/to/node_modules/karma-jasmine/lib/jasmine.js:2187:24
     path/to/node_modules/karma-jasmine/lib/jasmine.js:2167:23' }, pending : undefined, processScheduled : false } } to be rejected with { myError : { error : 'error_message' } }.

So I started to think Chrome results were false positive, and I needed to rewrite the async tests: hence I tried with something like this plunkr , but now the tests fail both in PhantomJs and Chrome with the expected timeout message:

timeout: timed out after 1500 msec waiting for A should catch an error

NB: I can't update Jasmine to version 2.0 and use the done parameter mechanism now and if I got it right I should not even manually trigger a $rootScope.$apply/$digest when using jasmine-promise-matchers .

How can I write my async tests properly for this kind of async functions catching custom errors and async functions in general?

Answer 1

Angular 'async' tests are generally synchronous, thus waitsFor and runs are unnecessary and apparently harmful.

Indeed, jasmine-promise-matchers don't need to trigger a digest manually to execute $q promises since this is done internally.

The problem here is race condition. First runs seems to run after $rootScope.$digest() , and catch block is never executed - so is second runs .

Instead, it should be tested synchronously:

  it('it actually throws an error, yay', function () {
    var promise = HandleService.A();

    expect(promise).toBePromise();
    expect(promise).toBeRejectedWith(jasmine.objectContaining({
      myError: {error: 'error_message'}
    }));
  });