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Re: [ydn-javascript] YUI Test, unit test for an asynchronous API

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  • Joe C
    Nicholas, Ok, yes, the resume() concept will fulfill my requirements. I look forward to version 2.4 Joe ... Nicholas, Ok, yes, the resume() concept will
    Message 1 of 4 , Nov 30, 2007

      Ok, yes, the resume() concept will fulfill my requirements.

       I look forward to version 2.4


      On Nov 29, 2007 2:57 PM, Nicholas Zakas < nzakas@...> wrote:

      Hi Joe,


      There's actually two ways to use the new wait() method. The first is to use it like setTimeout(), as I described. The second is to pass in no arguments at all, which causes the entire test process to stop. You can then resume the process by calling resume(). In your case, this may be more reasonable. Still, from your description, this may be a bit tricky to test. I think something like the following would work:


      testMyFunction: function () {


          var that = this;

          myfunction(inputdata, function(outputData){


             //restart the test


                  YAHOO.util.Assert.areEqual(5, outputData.value);




          //wait until resume() is called




      This should work to test your function assuming it behaves the way I think it does (using setTimeout() to call the callback function?). It may be a little trickier to determine if the callback function was ever called. If you're using setTimeout(), you are virtually guaranteed that the function will be called, so is that a major concern for you?





      From: Joe C [mailto:joe.jconti@...]
      Sent: Thursday, November 29, 2007 11:39 AM
      To: Nicholas Zakas
      Subject: Re: [ydn-javascript] YUI Test, unit test for an asynchronous API


      Hi Nicholas,

      Thanks for responding. I'm not sure adding wait(...) time to YUI Test framework will help me. Here is a little more information on what I'm trying to do.

      The function I want to test has an API that looks like this:


      The first argument is some object and the second is a callback function that fires when 'myfunction' is complete. The output data from the function is called asynchronously and is dumped to a callback function

      function callbackFcn(outputdata)
         // do stuff with outputdata

      I'd like to add a test point that verifies 'outputdata' for correctness. I can't call assertEquals(...) within callbackFcn() because the YUI test harness will not be in the call stack.

      function callbackFcn(outputdata)
         assertEquals(true,...); // doesn't work, results in exception not YUI error

      In your description of 2.4 below, it appears that I have pass in a wait time. After that time is up, the assertEquals(...) runs. Is that correct?

      The problem with that design is that I now have to hard code wait times into my tests. I'd rather not have to do that. I'd like for the assertEqual comparison to run immediately after the callback function fires. I don't want to add a time buffer since that could slow my tests down and lead to guess work on my part.

      Another way to think about it, there are two failure modes with any asynchronous API:
      a) callbackFcn never firing
      b) invalid outputdata

      I'm more interested in testing for b. Case a is not something I'm concerned with. If it does happen, my entire test would hang it would be clearly obvious something fundamental is wrong.

      Let me know if this doesn't clear things up,


      On Nov 26, 2007 3:25 PM, Nicholas Zakas <nzakas@... > wrote:

      Hi Joe,


      Asynchronous testing is not possible in the 2.3 version of YUI Test. However, it will be available in the 2.4 version via the wait() method. It's a little bit difficult to tell what you're trying to accomplish from your code, but in 2.4 you'll be able to do something like this:


      testFoo : function(){




          }, 5000);   //wait 5 seconds



      If you can hold on until 2.4, this job will become much easier for you. J




      From: ydn-javascript@yahoogroups.com [mailto:ydn-javascript@yahoogroups.com] On Behalf Of Joe C
      Sent: Wednesday, November 14, 2007 6:16 AM
      To: ydn-javascript@yahoogroups.com
      Subject: [ydn-javascript] YUI Test, unit test for an asynchronous API



      I would like advice on a good strategy for a unit test on an API that is asynchronous. I want to verify the results of an API takes in a callback function that will fire at a later time. I don't want to have to use polling either - I'd prefer something more elegant.

      Here is what I'm doing now:

      testFoo : function () {
            myfunction(...,mycallback); //  mycallback fires asynchronously 

      mycallback: function(response) {
          var Assert = YAHOO.util.Assert ;

      This design doesn't work through because the Assert is called from mycallback and not a test* function.

      I get an error in firebug:
      "uncaught exception: ComparisonFailure: Values should be equal. Expected: false (boolean) Actual:true (boolean)"

      This error is expected because the YUI Test infrastructure is designed to catch these exceptions from the test* functions.




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