"store c into 'empty';";
org.apache.pig.newplan.logical.relational.LogicalPlan newLogicalPlan = migratePlan(query);
assertEquals( 1, newLogicalPlan.getSources().size() );
LOLoad load = (LOLoad) newLogicalPlan.getSources().get(0);
Map<Long,Set<String>> annotation =
(Map<Long, Set<String>>) load.getAnnotation(MapKeysPruneHelper.REQUIRED_MAPKEYS);
assertNotNull(annotation);
assertEquals( 1, annotation.keySet().size() );
Integer[] keySet = annotation.keySet().toArray( new Integer[0] );
assertEquals( new Integer(0), keySet[0] );
Set<String> keys = annotation.get(0);