String getProviderId() {
    return configuration.get(PROVIDER_ID).orElseThrow(() -> new IllegalArgumentException("Provider ID is missing"));
  }
@Test
  public void fail_to_get_provider_id_when_null() {
    assertThatThrownBy(() -> underTest.getProviderId())
      .isInstanceOf(IllegalArgumentException.class)
      .hasMessage("Provider ID is missing");
  }