@Test
public void toJsonReturnsExpected() {

    final PolicyErrorResponse underTest =
            PolicyErrorResponse.of(TestConstants.Policy.POLICY_ID,
                    TestConstants.Policy.POLICY_NOT_ACCESSIBLE_EXCEPTION,
                    TestConstants.EMPTY_DITTO_HEADERS);
    final JsonObject actualJsonCreated = underTest.toJson(FieldType.regularOrSpecial());
    assertThat(actualJsonCreated).isEqualTo(KNOWN_JSON);
}