setTimeout/setInterval do not catch errors

[polotek]

Foounit has waitFor and waitForTimeout keywords for doing asynchronous testing. But these aren't good for the simple use case of running a simple function once. What I'm doing is mocking ajax calls. Here's a simplified example.

var fakeAjax = {
   send: function(req) {
      var fakexhr;
      foounit.setTimeout(function() {
          req.success && req.success('data', 'success', fakeXHR);
      }, 10);
   }
}

The problem comes in when I want to put expect statements inside the success function. Since setTimeout isn't test aware, the errors propagate to the top of the runtime but do not make the test fail. Here's the simplest test for this issue.

foounit.add(function (kw){ with (kw){
  describe('waitFor', function() {
    it('fails if timeout throws', function() {
      var end = false;
      foounit.setTimeout(function() {
        end = true;
        expect(false).to(beTrue);
      }, 100);

      waitFor(function() {
        expect(end).to(beTrue);
      }, 1000);
    });
  });
}});

This test passes, but the expect in setTimeout should be caught and cause it to fail.