erp5_web_renderjs_ui: Add a small delay during language change.

In order to stabilise UI tests which are waiting for the loading animation
to play during language change.
Pick a small delay so users should not notice (value suggested by Romain).

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_pt_language_js.js

@@ -22,7 +22,11 @@
     .declareMethod("render", function () {
       var gadget = this;
 
-      return new RSVP.Queue()
+      return new RSVP.Queue(
+	  // Stabilise UI tests with a tiny delay, which should be unnoticeable
+	  // to users.
+          RSVP.delay(200)
+        )
         .push(function () {
           return RSVP.all([
             gadget.getUrlForList([{command: 'history_previous'}]),

[Vincent Pelletier]

@romain: notification just so you know I pushed this.

[Romain Courteaud]

@vpelletier FYI, I tried today to extend this idea to all pages, so that the loader is display for a minimal amount of time, but I don't like the result currently, as it adds flickering (I feel the delay between the page and the header rendering). I should find a way to improve this.

[Vincent Pelletier]

FWIW, 60fps means 16.7ms per frame. Maybe a delay of 10ms would be less noticeable ? I do not know if it would still work reliably for the purpose of stabilising tests.

Either way, I feel the current approach used in tests is very hackish. Would it be possible to have some dummy tag attribute modified whenever a load happened, and to trigger selenium waits on it ? (fetch current value from DOM into some variable, trigger change, wait until value in DOM is different from variable)