public static LookupResult single(final CharSequence singleValue) {
        return multi(singleValue, Collections.singletonMap(SINGLE_VALUE_KEY, singleValue));
    }
@Test
    public void serializeSingleNumber() {
        final LookupResult lookupResult = LookupResult.single(42);
        final JsonNode node = objectMapper.convertValue(lookupResult, JsonNode.class);

        assertThat(node.isNull()).isFalse();
        assertThat(node.path("single_value").asInt()).isEqualTo(42);
        assertThat(node.path("multi_value").path("value").asInt()).isEqualTo(42);
        assertThat(node.path("ttl").asLong()).isEqualTo(Long.MAX_VALUE);
    }