What is the recommended way to grab test bases from the test area of another
module? Right now, I'm doing the moderately ugly:

 sys.path.append(str(py.path.local(autopath.pypydir).join('module', 'cpyext', 'test')))
 from test_cpyext import AppTestCpythonExtensionBase

which works fine, but surely there must be a better way?