def METHOD_NAME(self):
    self.prepare_data('password')
    assertion = JWTBearerGrant.sign(
        'bar', issuer='jwt-client', audience='https://i.b/token',
        subject=None, header={'alg': 'HS256', 'kid': '2'}
    )
    rv = self.client.post('/oauth/token', data={
        'grant_type': JWTBearerGrant.GRANT_TYPE,
        'assertion': assertion
    })
    resp = json.loads(rv.data)
    self.assertEqual(resp['error'], 'unauthorized_client')