### Question:
JdbcIntermediateFederatedProvider implements IntegralIntermediateFederatedProvider { @Nullable @Override public IntegralIntermediateRdbmsProvider getSpecificServiceProvider(@NotNull final Rdbms rdbms) { final SpecificProvider sp = myBestProviders.get(rdbms); return sp != null ? sp.provider : null; } JdbcIntermediateFederatedProvider(); void registerProvider(@NotNull final IntegralIntermediateRdbmsProvider provider); void deregisterProvider(@NotNull final PrimeIntermediateRdbmsProvider provider); @NotNull @Override Set<Rdbms> supportedRdbms(); @NotNull @Override IntegralIntermediateFacade openFacade(@NotNull final String connectionString,
                                               @Nullable final Properties connectionProperties,
                                               final int connectionsLimit); @Nullable @Override IntegralIntermediateRdbmsProvider getSpecificServiceProvider(@NotNull final Rdbms rdbms);  }### Answer:
@Test public void the_UnknownDatabaseServiceProvider_is_registered() { PrimeIntermediateRdbmsProvider provider = myFederatedProvider.getSpecificServiceProvider(UnknownDatabase.RDBMS); assertThat(provider).isNotNull() .isInstanceOf(UnknownDatabaseProvider.class); }