Tests require mpi4py with openmpi.

Index: h5py/tests/test_file.py
--- h5py/tests/test_file.py.orig
+++ h5py/tests/test_file.py
@@ -875,6 +875,7 @@ class TestPickle(TestCase):
 # unittest doesn't work with pytest fixtures (and possibly other features),
 # hence no subclassing TestCase
 @pytest.mark.mpi
+@pytest.mark.skip(reason="fixture 'mpi_file_name' not present")
 class TestMPI:
     def test_mpio(self, mpi_file_name):
         """ MPIO driver and options """