def METHOD_NAME(self):
    BASE_API_URL = "https://systran_fake_server.invalid:5050"
    API_KEY = "a super key"
    base_content = io.BytesIO("Source content".encode("utf-8"))
    result_content = io.BytesIO("Translated".encode("utf-8"))
    responses.add(
        responses.POST,
        "{}{}".format(BASE_API_URL, FILE_TRANSLATION_ENDPOINT),
        body=result_content.read(),
        status=200,
        content_type="text/plain",
        stream=True,
    )
    translation_service = SystranTranslationService(api_url=BASE_API_URL, api_key=API_KEY)
    result = translation_service.translate_file(
        input_lang="fr",
        output_lang="en",
        binary_io=base_content,
        mimetype="text/plain",
    )
    assert result.read().decode("utf-8") == "Translated"