@Override
            public Result search(Query query, Execution execution) {
                query.trace(SOURCE1, 1);
                return execution.search(query);
            }
Test for federation searcher. The searcher is also tested in
com.yahoo.prelude.searcher.test.BlendingSearcherTestCase.

@author Arne Bergene Fossaa
container-search/src/test/java/com/yahoo/search/federation/FederationSearcherTestCase.java