def METHOD_NAME(self):
    """Check regex is used"""
    self._setup_config(bucket_alpha=['foo', 'bar'],
                       bucket_alpha_regex={'foo': '^[a-d]',
                                           'bar': '^[e-z]'})
    self.assertEqual(self.plugin._tmpl_bucket('alpha'), 'foo')
    self.assertEqual(self.plugin._tmpl_bucket('delta'), 'foo')
    self.assertEqual(self.plugin._tmpl_bucket('zeta'), 'bar')
    self.assertEqual(self.plugin._tmpl_bucket('Alpha'), 'A')