'Verify the request of refreshing an object.'

def test_refresh_custom_headers(self):

    self.instance.CUSTOM_HEADERS = {'Accept': 'application/vnd.github.drax-preview+json'}
    expected_headers = {'Accept': 'application/vnd.github.drax-preview+json'}
    self.instance.refresh()
    self.session.get.assert_called_once_with(self.url, headers=expected_headers)
