private SearchChain createSearchChain(ComponentId chainId,Searcher searcher) {
        return new SearchChain(chainId, searcher);
    }
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