dsID = new DataSetID( null, 1, "query" ); assertNull( dsID.toString( ) );
	public void testToString( )	{		DataSetID dsID = new DataSetID( "ds" );		assertEquals( "ds", dsID.toString( ) );		dsID = new DataSetID( new DataSetID( "parent" ), 1, "query" );		assertEquals( "{parent}.1.query", dsID.toString( ) );		dsID = new DataSetID( null, 1, "query" );		assertNull( dsID.toString( ) );		dsID = new DataSetID( new DataSetID(				new DataSetID( "grandpa" ),				0,				null ), 1, "query" );		assertEquals( "{{grandpa}.0.null}.1.query", dsID.toString( ) );		dsID = new DataSetID( new DataSetID( "parent" ), 1, null );		assertEquals( "{parent}.1.null", dsID.toString( ) );	}