Asynchronous injected JS doesn't get to finish

[danvk]

@ihodes ran into this, if you inject some JS along the lines of:

window.setTimeout(function() {
  // click something
}, 1000);

Then the screenshot gets taken before the click happens. The page.waitForReady function waits for XHRs to complete, but it doesn't wait for other async code to run. I'm not even sure if this is possible with Phantom.

[bslatkin]

Yeah this is hard. We could try to override setTimeout to register / wrap callbacks? What I worry about is it's often the case that a page always has N callbacks set at all times and the set of outstanding callbacks never goes to zero.

One option is to have a "trigger test end" callback in the global scope like window._dpxdt_Done(). Then the injectJs can set the whole page up, do its own timeouts, and trigger the load. You can boost the timeout to make room for this to happen, or maybe we could have another flag per test which says to always wait for the Done() call to happen?

[danvk]

The flag + done() approach would work; it's similar to how qunit solves the problem.

I'd like to look into how CasperJS implements its waitFor methods. It's a much nicer API if we can make it work.