@Test
    @Timeout(300)
    void testEmptyTracing() throws IOException, InterruptedException, ExecutionException {
        String expected = "{"
                + "    \"root\": {"
                + "        \"fields\": {"
                + "            \"totalCount\": 0"
                + "        },"
                + "        \"id\": \"toplevel\","
                + "        \"relevance\": 1.0"
                + "    }"
                + "}";
        Query q = new Query("/?query=a&tracelevel=0");
        Execution execution = new Execution(Execution.Context.createContextStub());
        Result r = new Result(q);

        execution.search(q);
        Execution e2 = new Execution(new Chain<Searcher>(), execution.context());
        Query subQuery = new Query("/?query=b&tracelevel=0");
        e2.search(subQuery);
        subQuery.trace("yellow", 1);
        q.trace("marker", 1);
        String summary = render(execution, r);
        assertEqualJsonContent(expected, summary);
    }
Functional testing of {@link JsonRenderer}.

@author Steinar Knutsen
@author bratseth
container-search/src/test/java/com/yahoo/search/rendering/JsonRendererTestCase.java