Yeah- I didn't think of that.  You could pull the decorator's logic into your test:

```
    def test_zeros(self):
        """ A very simple test that really checks the MPI comm. """
        nodes = [0, 1, 2, 3]
        comm = create_comm_with_list(self.nodes)
        if comm == MPI.COMM_NULL:
            pass
        else:
            size = len(self.nodes)
            nrows = size * 3
            a = dla.zeros((nrows, 20), comm=self.comm)
            expected = numpy.zeros((nrows // size, 20))
            assert_array_equal(a.local_array, expected)
```

(untested, just off the top of my head)