Async unit test pattern

[Günter Zöchbauer]

In async unit test I often see expectAsync used like this

Timer.run(expectAsync((){
  expect(true, equals(true));
}));


I think this is wrong because the test could already have been ended before `expectAsync()` is called.
I would use it like 

var done = expectAsync((){});
Timer.run((){
  expect(true, equals(true));
  done();
}));

Can the first version work?

I also read several times that returning a Future from a test would make the test wait until the Future completes.
This didn't work for me yet (worked for async calls in `setUp()` though)

Any thoughts about this?

[Florian Loitsch]

On Wed, Apr 23, 2014 at 8:23 AM, Günter Zöchbauer <gzo...@gmail.com> wrote:

In async unit test I often see expectAsync used like this

Timer.run(expectAsync((){


  expect(true, equals(true));


}));




I think this is wrong because the test could already have been ended before `expectAsync()` is called.
I would use it like 



var done = expectAsync((){});


Timer.run((){
  expect(true, equals(true));


  done();
}));



Can the first version work?

yes. You can rewrite your first example (with same semantics) as:

var t = expectAsync(() {

  expect(true, equals(true));

});

Timer.run(t);

So the expectAsync is called synchronously and not just when Timer.run is executed.

I also read several times that returning a Future from a test would make the test wait until the Future completes.
This didn't work for me yet (worked for async calls in `setUp()` though)


Any thoughts about this?

--
For other discussions, see https://groups.google.com/a/dartlang.org/
 
For HOWTO questions, visit http://stackoverflow.com/tags/dart
 
To file a bug report or feature request, go to http://www.dartbug.com/new

To unsubscribe from this group and stop receiving emails from it, send an email to misc+uns...@dartlang.org.

--
Give a man a fire and he's warm for the whole day,
but set fire to him and he's warm for the rest of his life. - Terry Pratchett

[Peter Ahé]

Perhaps I'm missing something, but I don't think that Timer.run can affect the evaluation order of its arguments. 

In this code:

Timer.run(expectAsync(...));

You should be able to rely on expectAsync being called synchronously. 

Cheers,

Peter

[Peter Ahé]

And that was essentially what Florian said. I misread his answer :-)

Cheers,

Peter

[Günter Zöchbauer]

Thanks for the response Florian and Peter!

I see now where I was mistaken.

the parens at `expectAsync( ... )` make it call and pass the result of course.

I interpreted it like it was written this way 

Timer.run(() => expectAsync(() { xxx }));

Cheers

Günter