@Test
public void toJsonReturnsExpected() {

    final FeatureCreated underTest =
            FeatureCreated.of(TestConstants.Thing.THING_ID, TestConstants.Feature.FLUX_CAPACITOR,
                    TestConstants.Thing.REVISION_NUMBER,
                    TestConstants.TIMESTAMP, TestConstants.EMPTY_DITTO_HEADERS,
                    TestConstants.METADATA);
    final JsonObject actualJson = underTest.toJson(FieldType.regularOrSpecial());
    assertThat(actualJson).isEqualTo(KNOWN_JSON);
}