Optional<String> getServiceProviderPrivateKey() {
    return configuration.get(SERVICE_PROVIDER_PRIVATE_KEY);
  }
@Test
  public void return_service_provider_private_key() {
    settings.setProperty("sonar.auth.saml.sp.privateKey.secured", "my_private_secret_private_key");

    assertThat(underTest.getServiceProviderPrivateKey()).hasValue("my_private_secret_private_key");
  }