public static EncryptedValue createUnset() {
        return builder().value("").salt("").isKeepValue(false).isDeleteValue(false).build();
    }
@Test
    void testUnset() throws Exception {
        final EncryptedValue value = EncryptedValue.createUnset();

        final String jsonString = objectMapper.writeValueAsString(TestDTO.create("abc123", value));
        final JsonNode node = objectMapper.readValue(jsonString, JsonNode.class);

        assertThat(node.path("password_value").path("is_set").isBoolean()).isTrue();
        assertThat(node.path("password_value").path("is_set").asBoolean()).isFalse();
    }