@Test
    @Timeout(300)
    void testNullField() throws InterruptedException, ExecutionException, IOException {
        String expected = "{"
                + "    \"root\": {"
                + "        \"children\": ["
                + "            {"
                + "                \"fields\": {"
                + "                    \"null\": null"
                + "                },"
                + "                \"id\": \"nullstuff\","
                + "                \"relevance\": 1.0"
                + "            }"
                + "        ],"
                + "        \"fields\": {"
                + "            \"totalCount\": 1"
                + "        },"
                + "        \"id\": \"toplevel\","
                + "        \"relevance\": 1.0"
                + "    }"
                + "}";
        Result r = newEmptyResult();
        Hit h = new Hit("nullstuff");
        h.setField("null", null);
        r.hits().add(h);
        r.setTotalHitCount(1L);
        String summary = render(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