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
assertEquals( 111, label.getPrivateStyle( ).getColor( ).getRGB( ) );
		
		designHandle.getCommandStack( ).undo( );
		assertEquals( 222, label.getPrivateStyle( ).getColor( ).getRGB( ) );
		
		designHandle.getCommandStack( ).redo( );
		assertEquals( 111, label.getPrivateStyle( ).getColor( ).getRGB( ) );
		
		designHandle.getCommandStack( ).redo( );
		assertEquals( 333, label.getPrivateStyle( ).getColor( ).getRGB( ) );
	}
	/**
	 * Tests the element reference update when user adds one library or drops
	 * it.
	 * 
	 * @throws Exception
	 *             if any exception.
	 */
	public void testElementReferenceAfterAddingOrDroppingLibrary( )
			throws Exception
	{
		openDesign( "DesignForTestingLibraryChange.xml" ); 
		
		LabelHandle label = (LabelHandle) designHandle.findElement( "label1" ); 
		assertEquals( "blue", label.getPrivateStyle( ).getColor( ) 
				.getStringValue( ) );
		
		StyleHandle style = designHandle.findNativeStyle( "style1" ); 
		style.drop( );
		assertEquals( "green", label.getPrivateStyle( ).getColor( )