Mock final class in Spock

Question

Can spock mock final classes? If so, how? Search results brought up this gist, which would seem to imply so, but I can't find any examples of doing so. I've also found forum posts that say mocking final classes isn't supported.

Answer 1

This specification:

@Grab('org.spockframework:spock-core:1.0-groovy-2.4')
@Grab('cglib:cglib-nodep:3.1')

import spock.lang.*

class Test extends Specification {
    def 'lol'() {
        given: 
        def s = Mock(String) {
            size() >> 10
        }

        expect:
        s.size() == 10        
    }
}

ends with the following exception:

JUnit 4 Runner, Tests: 1, Failures: 1, Time: 29 Test Failure:
lol(Test) org.spockframework.mock.CannotCreateMockException:
Cannot create mock for class java.lang.String because Java mocks cannot mock final classes.
If the code under test is written in Groovy, use Groovy mock.

The solution is to use GroovyMock:

@Grab('org.spockframework:spock-core:1.0-groovy-2.4')
@Grab('cglib:cglib-nodep:3.1')

import spock.lang.*

class Test extends Specification {
    def 'lol'() {
        given: 
        def s = GroovyMock(String) {
            size() >> 10
        }

        expect:
        s.size() == 10        
    }
}

Which works well.