Allow for additional checks

[mbrodala]

The Check task currently checks for manager, language, extensions and drivers.

However, this is rather limiting and does not allow for performing additional checks, e.g. PHP upload_max_filesize and similar.

I'd suggest adding a additional method to the CheckStrategyInterface which could be used to perform and return these kind of additional checks.

[Anahkiasen]

Well you could already use the before and after hooks for this no? Those should fail the task if you return false in them in theory

[mbrodala]

@Anahkiasen You may be right about this, gotta give this a try ASAP. :-)