Re: Writing ERT tests for asynchronous events

[Michael Albinus <michael.albinus@gmx.de>]

Alex Bennée <kernel-hacker@bennee.com> writes:

> Hi,

Hi Alex,

> Is there any support in ERT for things that have asynchronous behaviour?

I don't believe so.

> For example I want my test to kick off something using a url fetch
> (against a server running in the same emacs) and then once the
> transaction has completed test things have worked as expected
> using the ert operators.

If you are doing something asynchronously, certainly there is a hook you
can register your own function which is called when the asynchronous
action has been finished or a related event has happened. Add your own
function to this hook, which sets a bit or so.

In your ert test case, after invoking the asynchronous action, run a
timer. If the proper bit hasn't been set in time, let the test fail.

For example, see the Emacs repo, file test/automated/file-notify-tests.el,
function file-notify-test02-events, where I have implemented something
similar. file-notify--test-event-handler is my function to check
something and to set the result bits in the variable
file-notify--test-results. After waiting for 5 seconds, that variable is
checked for unsuccesful test results.

> Cheers,
>
> Alex Bennée

Best regards, Michael.