@Test
public void toJsonReturnsExpected() {

    final ModifySubjects underTest =
            ModifySubjects.of(TestConstants.Policy.POLICY_ID,
                    TestConstants.Policy.LABEL, TestConstants.Policy.SUBJECTS, TestConstants.EMPTY_DITTO_HEADERS);
    final JsonObject actualJson = underTest.toJson(FieldType.regularOrSpecial());
    assertThat(actualJson).isEqualTo(KNOWN_JSON);
}