@Test
public void toJsonWithPolicyIdToCopyReturnsExpected() {

    final JsonObject expected = KNOWN_JSON.set(ModifyThing.JSON_POLICY_ID_OR_PLACEHOLDER, POLICY_ID_TO_COPY);
    final ModifyThing underTest =
            ModifyThing.withCopiedPolicy(TestConstants.Thing.THING_ID, TestConstants.Thing.THING, POLICY_ID_TO_COPY,
                    TestConstants.EMPTY_DITTO_HEADERS);
    final JsonObject actualJson = underTest.toJson(FieldType.regularOrSpecial());
    assertThat(actualJson).isEqualTo(expected);
}