def METHOD_NAME(self, svc, customer_client):
    result = svc.get_sso_redirect(
        document_url="vitalsource://book/bookID/BOOK-ID/cfi/CFI",
        user_reference=sentinel.user_reference,
    )
    customer_client.get_sso_redirect.assert_called_once_with(
        sentinel.user_reference,
        "https://hypothesis.vitalsource.com/books/BOOK-ID/cfi/CFI",
    )
    assert result == customer_client.get_sso_redirect.return_value