def METHOD_NAME(self):
    super(TestPreviewMode, self).METHOD_NAME()
    self.stderr = six.StringIO()
    self.stderr_patch = mock.patch('sys.stderr', self.stderr)
    self.stderr_patch.start()
    self.full_config = {'profiles': {}}
    # Implementation detail, but we want to patch out the
    # session config, as that's the only way to control
    # preview services.
    self.driver.session._config = self.full_config