Update: I was able to partially duplicate this issue. It's tracked in bug 274729.

Adopters and the community do care if your tests pass and if they can get them to pass on their systems. There was a recent newsgroup posting within the WTP newsgroup asking about JSDT test failures. The phrase that stood out.

I see that there is a lot of errors (7) and failures (47) in 168 tests. I see assertations that will fail alwa[y]s:

assertTrue(TagElement.TAG_SINCE.equals("@since")); //$NON-NLS-1$
because of
public static final String TAG_SINCE = " "; //$NON-NLS-1$

So, this raises question - is JSDT really working if it has no tests?
Webtools is not alone in this, it just happens to be the one I saw today. While unit tests may not seem important. There are those in the adopter and user community that use them as a guide to whether they want to even try to use the code. Keep them green and clean.