// also test cloning
ps01.set( "a", "-" );
ps01.set( "b", "-" );
ps01.set( "c", "-" );
PropertySet ops = opsm01.merge();
assertEquals( "a01", ops.get("a") );
assertEquals( "b02", ops.get("b") );
assertEquals( "c03", ops.get("c") );
assertEquals( "d03", ops.get("d") );
}