@Test
public void retrieveThingToAdaptable() {

    final TopicPath topicPath = topicPath(TopicPath.Action.RETRIEVE);
    final JsonPointer path = JsonPointer.empty();
    final Adaptable expected = Adaptable.newBuilder(topicPath)
            .withPayload(Payload.newBuilder(path).build())
            .withHeaders(TestConstants.HEADERS_V_2)
            .build();
    final RetrieveThing retrieveThing =
            RetrieveThing.of(TestConstants.THING_ID, TestConstants.HEADERS_V_2_NO_CONTENT_TYPE);
    final Adaptable actual = underTest.toAdaptable(retrieveThing, channel);
    final JsonifiableAdaptable jsonifiableAdaptable =
            ProtocolFactory.wrapAsJsonifiableAdaptable(actual);
    final JsonObject jsonObject = jsonifiableAdaptable.toJson();
    assertWithExternalHeadersThat(actual).isEqualTo(expected);
}