Without having done actual research, and depending on my personal experience alone, I would assert that in PHP userland ...
- There are maybe 20 or more general-purpose CMSes.
- There are perhaps 50 or more public frameworks (of varying quality and approach).
- There are easily 100 or more templating libraries (even if most of them can be grouped under 4 or 5 approaches).
- There appear to be only 5 unit-test systems: PhpUnit, SimpleTest, Solar_Test, PHPT, and Lime.
Dispute the specific numbers all you like; they're not the point. The point is that CMSes, frameworks, template systems, etc. seem to be a very common artifact among PHP developers, but writing (and then publishing) unit-test systems does not seem anywhere near as common an obsession.
What does this say, if anything, about the attention given to unit-testing among PHP developers?
Note that this is an *off-the-cuff opinion* and a *request for comment*, and nothing else. (Some folks get testy about testing; please remember to be nice while commenting. ;-)
Update: And there are only 3 or 4 documentation systems: PhpDocumentor, Doxygen, and Solar_Docs, along with the various combinations of DocBook tools that Zend, PEAR, and PHP are using. I wonder how that enters into it, if at all.