@Test
public void createInstanceFromMinimalMap() {

    final Map<String, String> validHeaders = new HashMap<>();
    validHeaders.put(MessageHeaderDefinition.DIRECTION.getKey(), MessageDirection.TO.toString());
    validHeaders.put(MessageHeaderDefinition.SUBJECT.getKey(), SUBJECT);
    validHeaders.put(MessageHeaderDefinition.THING_ID.getKey(), THING_ID.toString());
    final MessageHeaders messageHeaders = MessageHeadersBuilder.of(validHeaders).build();
    assertThat(messageHeaders).containsAllEntriesOf(validHeaders);
}