Spec has no expectations - Jasmine testing the callback function

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I have a method which is being called using a d3 timer. Whenever the method is called, the method emits an object with a couple of values. One of the values increases over time. I would like to write a test to check whether the values are in the ascending order or not (i.e., increasing over time or not).

So, to tackle this, In my test, I subscribe to the event emitter and inside the subscription, I am pushing the object which I receive into a local array. And then, I am expecting the array[i] to be less than the array[i+1]. I think my logic is perfectly correct but I am not sure why I am getting an error from Jasmine saying that the spec has no expectations even though I have one.

Here is the code:

let x = d3.timer((elapsed) => { 
    this.method(); // call the function
    if(elapsed >= 500) {
     x.stop(); // stops the timer.
    }
});

method(elapsed) {
 // do something
 if(elapsed > 500) {
   this.output.emit({x: somevalue, y: somevalue, f: increasingvalue });
 }
}

The Jasmine Spec:

it('my spec', inject([JumpService], (service: JumpService) =>{
  array = [];
  //service calls the method
  service.output.subscribe(e => {
   array.push(e);
   // A console statement here will give me the length and the object pushed.
   for(let i = 0; i< array.length - 1; i++) {
    expect(array[i].f).toBeLessThan(array[i+1].f);
   }

  });

}));

Am I doing anything wrong here? How can I tackle such kind of a scenario? Please guide me in a right direction.

Thank you.

In general, when testing the async callback functions, it is always important to expect the outputs of the test after the promises are resolved. You can use the Angular test bed framework's tick() with the fakeAsync() or you can simply fallback to the Jasmine's general way of testing the async methods by using done()

Using done():

it('my spec', (done) => {
  array = [];
  service.output.subscribe(e => {
   array.push(e);
   for(let i = 0; i< array.length - 1; i++) {
    expect(array[i].f).toBeLessThan(array[i+1].f);
   }
   done();
  });
});

Hope this answer helps.

Note: I didn't had great luck with the fakeAsync() and tick(), so I am not including it in the answer. Sorry about that.

Failing test with no expectations · Issue #1467 · jasmine/jasmine , Would you agree on failing a test that doesn't have any expectations? a done callback, return a Promise , or declare the async function when Feature Request: Ability to configure 'spec has no expectations' as error #1740. Jasmine's existing functionality for detecting a spec that completes asyncronously, allows a spec to explicitly call a done callback, return a Promise, or declare the async function when calling it, so you might be able to provide some sort of wrapper for your codebase that maps over to one of those.

Try using async function from @angular/core/testing. It

Wraps a test function in an asynchronous test zone. The test will automatically complete when all asynchronous calls within this zone are done. Can be used to wrap an {@link inject} call.

Please find code example below:

it('...', async(inject([AClass], (object) => {
  object.doSomething.then(() => {
   expect(...);
  })
});

missing SPEC HAS NO EXPECTATIONS warning in result · Issue , When jasmine run test without expectation, it add text "SPEC HAS NO But with karma-jasmine, it is not possible check this state. appears in async tests, when user does not add done callback - test is marked as passed  When jasmine run test without expectation, it add text &quot;SPEC HAS NO EXPECTATIONS&quot; into test name. But with karma-jasmine, it is not possible check this state. Test is marked as pa

You should use done() at the end of the promise, but from Jasmine 2.8.0 that will not work because there is not implementation for a done() method. You should test your promises like:

it('does test promise',
    inject([MyService], async (myService: MyService) => {
        const result = await myService.serviceToTest()
        expect(result).not.toBeNull()
        expect(result).toBe('Some Value')
     })
)

Hope that this help you

JavaScript Asynchronous Testing Gotchas, It is really easy to get false positives when testing with mocha or jasmine, On top of that, in most javascript test suites, specs with no expectations within just pass. issues when you're dealing with assertions inside asynchronous callbacks:  This works fine, and the unit test fails if this http request is not made (which is good), and passes if the http request is made. The problem is that even thought it passes, Jasmine spec runner shows “SPEC HAS NO EXPECTATIONS” for this unit test, which makes me think I am not using the recommended way to test that a http call was made.

Jasmine spec has no expectation - angularjs - html, Jasmine spec has no expectation - angularjs. My test is covering the function call, but its not covering the .done callback seen here: So my question is, how  Finally, you can use the afterEach() function to reset the variables after each spec so you can have pure unit testing without the need to repeat initialization and cleanup code for each spec. The beforeEach() function is also perfectly combined with many Jasmine APIs such as the addMatchers() method to create custom matchers or also with the done() function to wait for asynchronous operations before continue testing.

getNumberOfUsers() subscription SPEC HAS NO EXPECTATIONS , getNumberOfUsers() subscription SPEC HAS NO EXPECTATIONS - angular. https://angular.io/guide/testing#component-with-async-service Jasmine 2.0 async orderOfferId) .subscribe( res => { // This part is not executed from Test var result​: of using the done() callback, like: describe('test', function () { it('should work',  When I execute test cases , I see a message SPEC HAS NO EXPECTATIONS for both test cases . I am wondering why it shows spec has no expectations. Then I followed the suggested solutions in this post: Spec has no expectations - Jasmine testing the callback function. Using done():

Testing Asynchronous Code • Angular, Jasmine has a built-in way to handle async code and that's by the passed in done function in the test specs. add a callback function (using the spy) which is called when and we can add our additional expectation here. and is not executed in the order it's written in. Anything less than this in terms of the observer is insufficient. It must be an object and it must have a method. So there we have it! A simple callback, a relatively straightforward and isolated test, and all scope is maintained by somewhat verbose but easily readable closures. A very serviceable implementation, and one which I use regularly.