@Test
public void testFromAdaptable() {

    final PolicyErrorResponse expected =
            PolicyErrorResponse.of(TestConstants.Policies.POLICY_ID, dittoRuntimeException);
    final TopicPath topicPath =
            TopicPath.newBuilder(TestConstants.Policies.POLICY_ID).policies().none().errors().build();
    final JsonPointer path = JsonPointer.empty();
    final Adaptable adaptable = Adaptable.newBuilder(topicPath)
            .withPayload(Payload.newBuilder(path)
                    .withValue(dittoRuntimeException.toJson(FieldType.regularOrSpecial()))
                    .build())
            .withHeaders(TestConstants.HEADERS_V_2)
            .build();
    final PolicyErrorResponse actual = underTest.fromAdaptable(adaptable);
    assertWithExternalHeadersThat(actual).isEqualTo(expected);
}