qunit: prevent slow script warnings in long testsuites

[dwt]

We've added this patch to our QUnit to prevent slow script warnings in IE and Firefox:

Index: agilo_pro/htdocs/js/tests/qunit/testrunner.js
===================================================================
--- agilo_pro/htdocs/js/tests/qunit/testrunner.js	(Revision 1844)
+++ agilo_pro/htdocs/js/tests/qunit/testrunner.js	(Arbeitskopie)
@@ -281,8 +281,14 @@
 }
 
 function process() {
+	var index = 0;
 	while(config.queue.length && !config.blocking) {
 		config.queue.shift()();
+		// prevent slow script warnings in long test suites
+		// do it only every tenth test though to minimize the performance hit this workaround has
+		if (index > 10)
+			return setTimeout(process, 0);
+		index++;
 	}
 }

This combines very nicely with #4857 as it allows one to disable auto reloading the testsuite during testsuite execution, instead of only after it has run through.

Another benefit of this is that in browsers that only have one JS Engine, so executing the tests in the background doesn't block all other tabs / windows completely.

[joern]

To make the testrunner even more responsive, each update should be interleaved with a timeout:

{{{function process() {

if (config.queue.length && !config.blocking) {

config.queue.shift()(); setTimeout(process, 13);

}

}}}}

The drawback here is that it actually degrades performance. Probably due to various DOM updates being skipped when the UI is blocked. That shouldn't stop this patch from being applied, but QUnit also needs some performance tuning.

[dwt]

We tried that too, but this degraded the performance of our testsuite by about 300% - which was unacceptable to us.

Thats why we choose to only set the timeout every 10th run through.

Regards, Martin

[john]

We're moving QUnit-related bugs off to the new QUnit issue tracker: ​http://github.com/jquery/qunit/issues

Please re-post the issue there.