Bug 200645 Can't save custom aggregate function's information into model in computed column page
model/org.eclipse.birt.report.model.tests/test/org/eclipse/birt/report/model/api/ComputedColumnHandleTest.java
column.setName( "column1" ); 
		column.setExpression( "expression 1" ); 
		data.addColumnBinding( column, false );
		column = StructureFactory.createComputedColumn( );
		argument = StructureFactory.createAggregationArgument( );
		argument.setName( "argu3" ); 
		argument.setValue( "value3" ); 
		column.addArgument( argument );
		
		argument = StructureFactory.createAggregationArgument( );
		argument.setValue( "value4" ); 
		column.addArgument( argument );
		
		column.setName( "column2" ); 
		column.setExpression( "expression 2" ); 
		try
		{
			data.addColumnBinding( column, false );
			fail( );
		}
		catch ( PropertyValueException e )
		{
			assertEquals(
					PropertyValueException.DESIGN_EXCEPTION_VALUE_REQUIRED, e
							.getErrorCode( ) );
		}
	}
}