unable to resolve class spock.lang.Specification

[mrsa...@gmail.com]

I'm trying to use spock.

I've installed the plugin, I use grails-2.2.4, and set up Buildconfig as said in the plugin page.

I use netbeans as ide and when I create a test file like this:

package supplierregister

import grails.test.mixin.*

@TestFor(Sector)

class SectorSpec extends spock.lang.Specification {

the ide says: unable to resolve class spock.lang.Specification.

Why?