Unit testing custom validator of command object with dependency - unit-testing

Question

I have a command object for registering user, and I want to check how old is the user. This command object has a service dependency. How can I test custom validator for my dateOfBirth property? As it looks now is taken straight from documentation, here.
class RegisterUserCommand {
def someService
String username
String password
String password2
String email
Date dateOfBirth
static constraints = {
// other constraints
dateOfBirth blank: false, validator: {val, obj ->
return obj.someService.calculateAge(val) >= 18
}
}
So basically the question is: how can I mock 'obj' parameter of the validator closure?

Answer 1

The easiest way to test validation on a command object is to use GrailsUnitTestCase.mockForConstraintsTests. A mock validate method will be applied to your command object, and you can just call validate() like you would outside of a test.
Here's an example of how you could write your unit test. The blank constraint isn't meaningful for dates, so I've changed it to nullable: false.
import grails.test.GrailsUnitTestCase
class RegisterUserCommandTests extends GrailsUnitTestCase {
RegisterUserCommand cmd
protected void setUp() {
super.setUp()
cmd = new RegisterUserCommand()
mockForConstraintsTests RegisterUserCommand, [cmd]
}
void testConstraintsNull() {
cmd.dateOfBirth = null
cmd.someService = [calculateAge: { dob -> 18 }]
def result = cmd.validate()
assert result == false
assert cmd.errors.getFieldErrors('dateOfBirth').code == ['nullable']
}
void testConstraintsCustom() {
cmd.dateOfBirth = new Date()
cmd.someService = [calculateAge: { dob -> 17 }]
def result = cmd.validate()
assert result == false
assert cmd.errors.getFieldErrors('dateOfBirth').code == ['validator.invalid']
}
}
Note that your service won't get injected in a unit test (it will in an integration test though), so you'll either need to mock it, as above, or create an instance and assign it to cmd.someservice.