Support FreeBSD in tests?

[frozencemetery]

What went wrong?

It's expected that heimdal isn't supported by tests. But krb5 should be; however, it fails with what appears to be a k5test problem:

EE
======================================================================
ERROR: Failure: TypeError (expected str, bytes or os.PathLike object, not NoneType)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/nose/failure.py", line 39, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/usr/local/lib/python3.7/site-packages/nose/loader.py", line 417, in loadTestsFromName
    addr.filename, addr.module)
  File "/usr/local/lib/python3.7/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/usr/local/lib/python3.7/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/home/vagrant/.venv/lib/python3.7/imp.py", line 234, in load_module
    return load_source(name, filename, file)
  File "/home/vagrant/.venv/lib/python3.7/imp.py", line 171, in load_source
    module = _load(spec)
  File "<frozen importlib._bootstrap>", line 696, in _load
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/usr/home/vagrant/python-gssapi/gssapi/tests/test_high_level.py", line 16, in <module>
    import k5test.unit as ktu
  File "/home/vagrant/.venv/lib/python3.7/site-packages/k5test/__init__.py", line 1, in <module>
    from k5test.realm import K5Realm  # noqa
  File "/home/vagrant/.venv/lib/python3.7/site-packages/k5test/realm.py", line 92, in <module>
    'kdb'),
  File "/home/vagrant/.venv/lib/python3.7/posixpath.py", line 80, in join
    a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not NoneType

======================================================================
ERROR: Failure: TypeError (expected str, bytes or os.PathLike object, not NoneType)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/nose/failure.py", line 39, in runTest
    raise self.exc_val.with_traceback(self.tb)
  File "/usr/local/lib/python3.7/site-packages/nose/loader.py", line 417, in loadTestsFromName
    addr.filename, addr.module)
  File "/usr/local/lib/python3.7/site-packages/nose/importer.py", line 47, in importFromPath
    return self.importFromDir(dir_path, fqname)
  File "/usr/local/lib/python3.7/site-packages/nose/importer.py", line 94, in importFromDir
    mod = load_module(part_fqname, fh, filename, desc)
  File "/home/vagrant/.venv/lib/python3.7/imp.py", line 234, in load_module
    return load_source(name, filename, file)
  File "/home/vagrant/.venv/lib/python3.7/imp.py", line 171, in load_source
    module = _load(spec)
  File "<frozen importlib._bootstrap>", line 696, in _load
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/usr/home/vagrant/python-gssapi/gssapi/tests/test_raw.py", line 8, in <module>
    import k5test.unit as ktu
  File "/home/vagrant/.venv/lib/python3.7/site-packages/k5test/__init__.py", line 1, in <module>
    from k5test.realm import K5Realm  # noqa
  File "/home/vagrant/.venv/lib/python3.7/site-packages/k5test/realm.py", line 92, in <module>
    'kdb'),
  File "/home/vagrant/.venv/lib/python3.7/posixpath.py", line 80, in join
    a = os.fspath(a)
TypeError: expected str, bytes or os.PathLike object, not NoneType

----------------------------------------------------------------------
Ran 2 tests in 0.087s

FAILED (errors=2)

How do we reproduce?

sudo pkg install py37-{setuptools,virtualenv,cython,nose,parametrized,six,flake8} krb5
virtualenv --system-site-packages ~/.venv
source ~/.venv/bin/activate
pip install -r test_requirements.rst
python3 setup.py build_ext --inplace
python3 setup.py nosetests

Component versions (python-gssapi, Kerberos, OS / distro, etc.)

FreeBSD 12.2, krb5-1.18.2, python-gssapi from HEAD