@Test
    void testProviderSelectionFromQueryProperties() {
        SearchChainRegistry registry = new SearchChainRegistry();
        registry.register(new Chain<>("provider1", new MockProvider("provider1")));
        registry.register(new Chain<>("provider2", new MockProvider("provider2")));
        registry.register(new Chain<>("default", createMultiProviderFederationSearcher()));
        assertSelects("provider1", registry);
        assertSelects("provider2", registry);
    }
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