launchpad-dev team mailing list archive

[Ian Booth <ian.booth@xxxxxxxxxxxxx>]

Hi

You may have noticed a large number of changes to the Javascript and YUI
tests in recent updates to your devel branch. Here's a quick heads up on
what's been going on and what you should know moving forward.

At the recent Epic, we started a project to pull the lazr-js source code
into the Launchpad source tree. As part of the effort, it was of course
necessary to ensure that the existing lazr-js unit tests were run as
part of Launchpad's YUI test layer. In doing this, a number of areas for
improvement for Launchpad's YUI test framework became apparent. The
changes have all been done and landed. What you need to know to continue
writing YUI tests will be summarised below. The dev wiki has also been
updated:
https://dev.launchpad.net/JavascriptUnitTesting

== Source Code ==

The lazr-js source code have been brought into the Launchpad source tree
under lib/lp/app/javascript. So we have:

lib/lp/app/javascript/anim/...
lib/lp/app/javascript/anim/tests/...
lib/lp/app/javascript/overlay/...
lib/lp/app/javascript/overlay/tests/...
lib/lp/app/javascript/picker/...
lib/lp/app/javascript/picker/tests/...
etc

The previously separate Launchpad and lazr-js picker implementations
have been merged. lazr-js code which we were not using in Launchpad has
been deleted. Since we have test coverage and now full control over the
source code, feel free to make changes/improvemets/bug fixes etc just as
for other Launchpad source code.

The Javascript build process has had some radical surgery to simplify
the directory structure and Javascript packaging. The changes are
transparent to developers. Unless you want to know the gory detail, all
you need to know is that a make (clean) jsbuild will produce a
launchpad.js which Just Works.

== YUI Library ==

Previously, the YUI library was packaged as part of lazr-js. Now it's a
separate dependency, packaged as a tarball in download-cache. As with
other tarballs in the cache, we use versions.cfg to nominate what
version we want to build with. Currently it's 3.3, so that tarball
yui-3.3.tar.gz will be unpacked and used as part of the make process.

The outcome is that we can very easily now test new versions if YUI by
simply downloading the pre-packaged tarball off github and updating
versions.cfg.

== YUI Tests ==

Our YUI tests had a number of areas for improvement. The main issue is
that there was way too much cut'n'paste boiler plate.
1. Each html test harness had to define a <div id='log></div> to capture
the output.

2. Logged output was very hard to read inside the small log console
embedded in the page.

3. Lots of areas were there was cut'n'paste in the test files:
a. the html test harness (import of all the css styles)

b. the YUI object construction at the top of each test file
YUI({
... cut'n'paste configs ...
}).use(...)

c. the test run and logging code (the 15 lines of "Lock, stock and two
smoking barrels" javascript)


The refactoring that was done eliminates the above problems:
i. There's a new lib/lp/app/javascript/testing directory which contains
the common code and css for all tests.
--> yui config, css, common test code changed in one place

ii. the log div is constructed on the fly in the test setup code
--> no more <div id='log></div> required in html test harnesses

iii the test output is logged to both the browser console and the YUI
test console
--> logged output readable

iv. tests are run using a single line of Javascript:
Y.lp.testing.Runner.run(suite);
--> enough said

The wiki has the new harness and runner example code:
https://dev.launchpad.net/JavascriptUnitTesting

As before, the YUI tests are run using:
bin/test --layer=YUI

or can be run one suite at a time in the browser by loading the relevant
html test harness.

NB I have found that FF5 fails when running some of the tests. They work
fine in Chromium and python-htmlbrowser used by the test runner. I have
not yet tracked down the cause. The failing tests are from the (former)
lazr-js suite.

If there are any questions, please let me know.