I have never been a QA engineer. However, it doesn't require great experience
to see that the MW software development process is broken. I provide the
following comments not in a destructive spirit. The success of the MW software
is obvious. However, in my view unless the development process introduces some
QA procedures, the code eventually will collapse and its reputation will
degrade.
My interest in MW (the software, not the organization) is driven by a desire to
provide an enhancement in the form of an extension. So, I began by building a
small development environment on my machine (a work in progress). Having
developed software for other organizations, I intuitively sought out what I
needed in terms of testing in order to provide a good quality extension. This
meant I needed to develop unit tests for my extension and also to perform
regression testing on the main code base after installing it. Hence some of my
previous questions to this email list.
It soon became apparent that the MW development process has little or no
testing procedures. Sure, there are the parser tests, but I couldn't find any
requirement that developers had to run them before submitting patches.
Out of curiosity, I decided to download 1.16a (r52088), use the LocalSettings
file from my local installation (1.14) and run some parser tests. This is not a
scientific experiment, since the only justification for using these extensions
in the tests is I had them installed in my personal wiki. However, there is at
least one thing to learn from them. The results are:
Mediawiki 52088 Parser Tests
Extensions : 1) Nuke, 2) Renameuser, 3) Cite, 4) ParserFunctions, 5) CSS Style
Sheets, 6) ExpandTemplates, 7) Gadgets, 8) Dynamic Page List, 9) Labeled
Section Transclusion. The last extension has 3 require_once files: a) lst.php,
b) lsth.php, and c) compat.php.
Test Extensions ParserTests Test Fails
1 1,2,3,4,5,6,7,8,9 19
2 1 14
3 2 14
4 3 14
5 4 14
6 5 14
7 6 14
8 7 14
9 8 14
10 9 (abc) 19
11 9 (a) 18
12 9 (ab) 19
13 1,2,3,4,6,7 14
Note that the extension that introduces all of the unexpected parser test
failures is Labeled Section Transclusion. According to its documentation, it is
installed on *.wikisource.org, test.wikipedia.org, and en.wiktionary.org.
I am new to this development community, but my guess is since there are no
testing requirements for extensions, its author did not run parser tests before
publishing it. (I don't mean to slander him and I am open to the correction
that it ran without unexpected errors on the MW version he tested against.)
This rather long preamble leads me to the point of this email. The MW software
development process needs at least some rudimentary QA procedures. Here are
some thoughts on this. I offer these to initiate debate on this issue, not as
hard positions.
* Before a developer commits a patch to the code base, he must run parser tests
against the change. The patch should not be committed if it increases the
number of parser test failures. He should document the results in the bugzilla
bug report.
* If a developer commits a patch without running parser tests or commits a
patch that increases the number of parser test failures, he should be warned.
If he does this another time with some time interval (say 6 months), his commit
privileges are revoked for some period of time (say 6 months). The second time
he becomes a candidate for commit privilege revocation, they will be revoked
permanently.
* An extension developer also should run parser tests against a MW version with
the extension installed. The results of this should be provided in the
extension documentation. An extension should not be added to the extension
matrix unless it provides this information.
* A test harness that performs regression tests (currently only parser tests)
against every trunk versions committed in the last 24 hours should be run
nightly. The installed extensions should be those used on the WMF machines. The
results should be published on some page on the Mediawiki site. If any version
increases the number of parser test failures, the procedure described above for
developers is initiated.
* A group of developers should have the responsibility of reviewing the nightly
test results to implement this QA process.
I am sure there are a whole bunch of other things that might be done to improve
MW QA. The point of this message is to initiate a discussion on what those
might be.
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