private Chain<Searcher> chainedAsSearchChain(Searcher topOfChain) {
        List<Searcher> searchers = new ArrayList<>();
        searchers.add(topOfChain);
        return new Chain<>(searchers);
    }
DO NOT USE. Use RuleBaseTester instead

@author bratseth
container-search/src/test/java/com/yahoo/prelude/semantics/test/RuleBaseAbstractTestCase.java