@BeforeEach
    public void setUp() throws Exception {
        builder = new FederationConfig.Builder();
        chainRegistry = new SearchChainRegistry();
    }
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