private static void compareGroups( MVD mvd1, MVD mvd2 ) 
		throws MVDTestException
	{
		int numGrps1 = mvd1.numGroups();
		int numGrps2 = mvd2.numGroups();
		if ( numGrps1 != numGrps2 )
			throw new MVDTestException(
				"Number of groups in MVDs don't match" );
		for ( short gId=1;gId<=numGrps1;gId++ )
		{
			String gName1 = mvd1.getGroupName( gId );
			String gName2 = mvd2.getGroupName( gId );
			if ( !gName1.equals(gName2) )
				throw new MVDTestException(
					"Group names don't match" );
			short gParent1 = mvd1.getGroupParent( gId );
			short gParent2 = mvd2.getGroupParent( gId );
			if ( gParent1 != gParent2 )
				throw new MVDTestException(
					"Group parents don't match" );
		}
	}