@SuppressWarnings( "unchecked" )
  public List<? extends ConnectionDetails> getConnectionDetailsByScheme( String scheme ) {
    initialize();
    ConnectionProvider provider = connectionProviders.get( scheme );
    if ( provider != null ) {
      List<String> names = namesByConnectionProvider.get( provider.getName() );
      if ( names != null && !names.isEmpty() ) {
        List<ConnectionDetails> details = new ArrayList<>();
        for ( String name : names ) {
          details.add( detailsByName.get( name ) );
        }
        return details;
      }
    }
    return Collections.emptyList();
  }
@Test
  public void testGetConnectionDetailsBySchemeEmpty() {
    addOne();
    assertEquals( 0, connectionManager.getConnectionDetailsByScheme( DOES_NOT_EXIST ).size() );
  }