NEW Add FieldsValidator to ensure fields get validated

[GuySartorelli]

I've also created #10908 for some follow-up breaking changes that should be made in CMS 6.

Issue

• Validation in the cms does not properly validate form fields silverstripe-admin#1539

[GuySartorelli]

The changes to this file should be fine, since behat contexts aren't intended to be subclassed. This is effectively the same as a unit test fixture for some custom functionality we want to use in tests.

[GuySartorelli]

There's a new default validator in the composite validator now, so we have to change the logic in this test in order to reliably get the correct one.

[sabina-talipova]

Could we add additional test case for another fields if possible.

[GuySartorelli]

We can, but can you please explain why? We're not testing if all form fields have implemented good validation logic - we're just testing if this new validator type correctly validates all fields in the form. The type of the field isn't really relevant.

[sabina-talipova]

Sorry, I add this comment as my suggestion / question in other PR.
But my small concern and question, will this solution work if user decided somehow to override parent method or add another validator.

[GuySartorelli]

If the developer implements it like this, it will work:

public function getCMSCompositeValidator(): CompositeValidator
{
    $validator = parent::getCMSCompositeValidator();
    $validator->addValidator(MyValidator::create());
    return $validator;
}

If they implement it like this, then they are explicitly choosing to ignore all validators previously set, and we shouldn't in that case force a validator on them:

public function getCMSCompositeValidator(): CompositeValidator
{
    $validator = CompositeValidator::create();
    $validator->addValidator(MyValidator::create());
    return $validator;
}

The latter scenario is the equivalent of this code before the composite validator was introduced:

public function getCMSValidator()
{
    return MyValidator::create();
}

[sabina-talipova]

Cool! Sounds good!

[sabina-talipova]

Looks good. Test locally. Tests passed.