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
* <strong>Case1:</strong>
	 * <p>
	 * Design.label1 -> lib1.baseLabel
	 * <p>
	 * When dropping lib1, label1 in the design will be localized, the
	 * parent/child relationship is broken.
	 * <p>
	 * <strong>Case2:</strong>
	 * <p>
	 * Design.label1 -> lib1.baseLabel -> lib2.baseLabel2
	 * <p>
	 * When dopping <strong>lib2</strong>, label1 in the design will be
	 * localized. While lib2.baseLabel1 will not be affected.
	 * <p>
	 * 
	 * @throws Exception
	 */
	public void testDropLibrary( ) throws Exception
	{
		
		openDesign( "TestDropLibrary_1.xml" ); 
		LibraryHandle libHandle = (LibraryHandle) designHandle.getLibraries( )
				.get( 0 );
		TableHandle tableHandle = (TableHandle) designHandle
				.findElement( "table1" ); 
		TableItem parent = (TableItem) tableHandle.getExtends( ).getElement( );
		assertNotNull( parent );
		RowHandle rowHandle = (RowHandle) tableHandle.getDetail( ).get( 0 );
		CellHandle cellHandle = (CellHandle) rowHandle.getCells( ).get( 0 );
		cellHandle.setStringProperty( StyleHandle.COLOR_PROP, "black" );