private void assertUseByDefault(FederationConfig config, String chainName, boolean expectedValue) {
        FederationConfig.Target target = getTarget(config.target(), chainName);
        assertEquals(1, target.searchChain().size());
        assertEquals(expectedValue, target.searchChain().get(0).useByDefault());
    }
Test generated config for federation.
@author Tony Vaagenes
config-model/src/test/java/com/yahoo/vespa/model/container/search/searchchain/FederationTest.java