Custom validator name in grails 3 - unit-testing

Question

I am migrating a big project from grails 2.5.4 to 3.3.10. Everything is going well but I have a mayor problem in my domain objects. I use to write my custom validators this way:
class Person {
String name
static constraints = {
name: nullable: false, validator: validateName
}
static validateName = {
// validation code
}
}
Grails throws the following exception
No such property: validatorTest for class: org.grails.orm.hibernate.cfg.HibernateMappingBuilder
In grails 3.x this way of defining validators seems to be broken. I know the documentation says to use this way:
name nullable: false, validator: { // code }
But it is a LOT of code to rewrite in that case.
Is there a way to use the old method of defining validators?
Thanks

Answer 1

See the project at https://github.com/jeffbrown/alejandroveraconstraints.
https://github.com/jeffbrown/alejandroveraconstraints/blob/master/grails-app/domain/alejandroveraconstraints/Person.groovy:
// grails-app/domain/alejandroveraconstraints/Person.groovy
package alejandroveraconstraints
class Person {
String name
static constraints = {
name nullable: false, validator: Person.validateName
}
static validateName = {
it != 'Some Bad Name'
}
}
https://github.com/jeffbrown/alejandroveraconstraints/blob/6701f61d61dbbde34f4925d1bf418448eee0a729/src/test/groovy/alejandroveraconstraints/PersonSpec.groovy:
// src/test/groovy/alejandroveraconstraints/PersonSpec.groovy
package alejandroveraconstraints
import grails.testing.gorm.DomainUnitTest
import spock.lang.Specification
class PersonSpec extends Specification implements DomainUnitTest<Person> {
void "test validation"() {
expect:
!new Person(name: 'Some Bad Name').validate()
new Person(name: 'Some Good Name').validate()
}
}