This is related to another question I asked about trying to fail Hudson on a single unit test failure.
When I run Maven on my build standalone, it fails due to unit
What type of Hudson job did you create? I suspect it's the m2 project rather than the freestyle project. In the m2 project, Hudson will actually tweak the way your pom is configured so as to prevent failures and instead mark it as unstable. This was intentional.
Try setting maven.test.failure.ignore=false under the Advanced setting as I believe Hudson automatically sets that to true.