[webkit-dev] C++ unit tests for WebKit?

Hajime Morrita morrita at chromium.org
Wed Jul 11 17:27:50 PDT 2012

(Resending from the right address....)

FYI, Chromium port has some unit-like tests:

Apparently it is not community's responsibility to maintain these. But it
might be useful for developing some low-level standalone/low-level stuff
like collections and utilities if you are developing on Chromium port.

My feeling is that the lack of unit test is mixture of philosophical
decisions and technical limitations.
As Adam mentioned, Layout Tests for Web Platform features fit former, and
untested low level stuff fits later.

If we have some low-level/primitive component for building larger web
platform features, such primitives are worth unit-testing IMHO.
And TestWebKitAPI (or cr-port test in some case) is good place for them.

On Thu, Jul 12, 2012 at 8:48 AM, Adam Barth <abarth at webkit.org> wrote:

> On Wed, Jul 11, 2012 at 4:31 PM, Hans Muller <hmuller at adobe.com> wrote:
>> Thanks for the thoughtful reply.   It was exactly the "community's
>> conventions and customs" that I was trying to get a handle on.   Not to put
>> too fine a point on it, but I assume that adding unit tests to
>> TestWebKitAPI or writing tests that depend on APIs defined in Internals.idl
>> wouldn't be customary or conventional?
> As the name implies, TestWebKitAPI is mostly about testing the WebKit API
> (meaning the API that WebKit exposes to folks who use it as a library).
>  Your feature doesn't seem to involve any WebKit API, so I would steer
> clear of TestWebKitAPI.
> We're still feeling out when it's appropriate to test something via
> Internals.  One good use of Internals is to set a WebCore::Setting directly
> rather than having to create API for N different ports.  There's a risk
> that Internals will become a dumping group for random things, and this is
> something we try to look out for when reviewing changes to Internals.idl.
>> I'd been thinking about doing the latter (Internals.idl), just because it
>> would enable testing some low level classes before everything we're working
>> on had been integrated top to bottom.  Doing so could just be a private
>> temporary change, since eventually it will be possible to exercise the code
>> via public APIs.
> Obviously, you should feel free to do whatever is convenient in your own
> private branch.  For development on trunk, I would encourage you to try to
> get a basic version of your feature working end-to-end (so that it's
> testable via the web platform) and then to elaborate it incrementally.
>  That's not always possible, but it tends to be a good approach for
> generating test coverage.
> I'm happy to discuss this topic further in #webkit if that would be
> helpful to you.
> Adam
>> From: Adam Barth <abarth at webkit.org>
>> To: Hans Muller <hmuller at adobe.com>
>> Cc: Benjamin Poulain <benjamin at webkit.org>, Konrad Piascik <
>> kpiascik at rim.com>, webkit-dev <webkit-dev at lists.webkit.org>
>> Subject: Re: [webkit-dev] C++ unit tests for WebKit?
>> Generally speaking, WebKit's testing philosophy is to test at API
>> boundaries, typically either a given port's WebKit API or the web platform
>> API.  The benefit of that approach is that it makes it easier for us to
>> refactor the internals of WebCore without being constrained by fragile
>> tests---only by API commitments.
>> In the case of CSS Exclusions, it's likely valuable to think about how
>> you can test the feature via the web platform.  Developing a rich set of
>> tests that use web platform APIs has a number of follow-on benefits that
>> WebCore-internal testing doesn't, such as the ability to run the tests in
>> other browsers and to contribute them to the W3C as part of the standards
>> process.
>> Of course, this sort of one-size-fits-all testing strategy works well in
>> come cases in less well in others.  I understand that other projects have
>> different testing strategies that have worked well for them, but I would
>> encourage you to try our the community's conventions and customs for a
>> while to get a feel for which ones work well and which ones ought to be
>> improved.
>> Adam
>> On Wed, Jul 11, 2012 at 3:44 PM, Hans Muller <hmuller at adobe.com> wrote:
>>> It looks like Tools/TestWebKitAPI/Tests/WebCore just contains one small
>>> KURL test. I could certainly add more for the Exclusions shape classes,
>>> but I got that feeling that maybe you get about being the first to take a
>>> table at an empty restaurant.  Perhaps it's just that most of the C++
>>> classes in WebCore are too interdependent to merit unit testing?
>>> - Hans
>>> On 7/11/12 2:26 PM, "Benjamin Poulain" <benjamin at webkit.org> wrote:
>>> >On Wed, Jul 11, 2012 at 2:23 PM, Hans Muller <hmuller at adobe.com> wrote:
>>> >> Have the merits of C++ unit tests been debated before?  I noticed that
>>> >>a bug
>>> >> representing as much has been around since 2008
>>> >> (https://bugs.webkit.org/show_bug.cgi?id=21010).  The last comment
>>> >>(2009)
>>> >> concludes with: "I'd be interested to hear other's thoughts."
>>> >>Personally,
>>> >> I'd like to be able to include unit tests with worthy C++ classes,
>>> >>however I
>>> >> would also like to hear other's thoughts.
>>> >
>>> >That has been discussed before.
>>> >
>>> >We have some C++ tests, see Tools/TestWebKitAPI/Tests/
>>> >You can probably integrate yours in there.
>>> >
>>> >Cheers,
>>> >Benjamin
>>> _______________________________________________
>>> webkit-dev mailing list
>>> webkit-dev at lists.webkit.org
>>> http://lists.webkit.org/mailman/listinfo/webkit-dev
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo/webkit-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20120712/b6306f7e/attachment.html>

More information about the webkit-dev mailing list