Bug 183918 get relative file path of linkage library
model/org.eclipse.birt.report.model.tests/test/org/eclipse/birt/report/model/library/DesignLoadLibraryTest.java
*             if any exception
	 */
	public void testDataSetReference( ) throws Exception
	{
		openDesign( "DesignWithElementReferenceLibrary.xml" ); 
		DataSetHandle dataSet2 = designHandle.findDataSet( "dataSet2" ); 
		DataSetHandle libADataSet1 = designHandle.findDataSet( "LibA.dataSet1" ); 
		DataSetHandle dataSet4 = designHandle.findDataSet( "dataSet4" ); 
		assertEquals( "LibA.dataSet1", dataSet4.getExtends( ) 
				.getQualifiedName( ) );
		TableHandle table1 = (TableHandle) designHandle.findElement( "table1" ); 
		assertNotNull( table1.getDataSet( ) );
		assertEquals( "LibA.dataSet1", table1 
				.getProperty( IReportItemModel.DATA_SET_PROP ) );
		assertNotNull( table1.getDataSet( ) );
		
		table1.setDataSet( dataSet2 );
		assertEquals(
				"dataSet2", table1.getStringProperty( TableHandle.DATA_SET_PROP ) ); 
		
		table1.setDataSet( libADataSet1 );
		assertEquals( "LibA.dataSet1", table1 
				.getStringProperty( IReportItemModel.DATA_SET_PROP ) );
		assertNotNull( table1.getDataSet( ) );
		
		designHandle.getCommandStack( ).undo( );
		assertEquals(
				"dataSet2", table1.getStringProperty( TableHandle.DATA_SET_PROP ) ); 
		assertEquals( dataSet2, table1.getDataSet( ) );