<p>I'm working on a free software (bsd license) project with others. We're searching for a system that check out our source code (svn) and build it also as test it (unit tests with Check / other tools).</p>

<p>It should have a webbased interface and generate reports.</p>

<p>I hope we don't have to write such a system from null by ourselves...</p>

I don't think that there's a buildsystem that is capable of doing all this tasks - but what about combining them?
SCons
is a nice buildsystem that runs on every machine that has
Python
. It can even build directly from
SVN
. For automatic building you can try
Buildbot
.