@Test
public void mapToBinaryMessageWithContentTypeOverride() {

    final Map<String, String> headers = Map.of(
            "content-type", "text/plain",
            "ditto-message-subject", "hello/world",
            "ditto-message-thing-id", "thing:id"
    );
    final String payload = "lorem ipsum dolor sit amet";
    underTest.configure(DefaultMappingConfig.of(ConfigFactory.empty()),
            DefaultMessageMapperConfiguration.of("RawMessage",
                    Map.of("incomingMessageHeaders", JsonObject.newBuilder()
                            .set("content-type", "application/octet-stream")
                            .build()
                    ), Map.of(), Map.of()));
    final List<Adaptable> adaptables =
            underTest.map(ExternalMessageFactory.newExternalMessageBuilder(headers)
                    .withText(payload)
                    .build());
    assertThat(adaptables).hasSize(1);
    final Signal<?> signal = ADAPTER.fromAdaptable(adaptables.get(0));
    assertThat(signal).isInstanceOf(SendThingMessage.class);
    final SendThingMessage<?> sendThingMessage = (SendThingMessage<?>) signal;
    assertThat(sendThingMessage.getEntityId().toString()).isEqualTo("thing:id");
    assertThat(sendThingMessage.getMessage().getPayload().orElseThrow())
            .isEqualTo(ByteBuffer.wrap(payload.getBytes()));
}