I tried running release 1.5 on CentOS 6.4 with the version of Mercurial and Python that comes with the OS and the tests failed with both SWIG and Subvertpy. Here's the output of hg version --svn with Subvertpy:
Mercurial Distributed SCM (version 1.4)
bindings: Subvertpy 0.8.10
With SWIG it's identical but just says SWIG for the bindings.
Is there anything that I can do to help further diagnose the issue?