Mocking is Not working in Spock Framework

I am trying to write Spock Framework instead of Junit,

Test Class :

class StudentServiceSpec extends Specification{

@Shared def studentDao
@Shared def studentService

def setupSpec(){
    studentDao = Mock(StudentDao)
    studentService = new StudentService(studentDao)
}

def "Get Student Details Based on StudentId"(){

    setup:
    1*studentDao.getStudent(67) >> new Student()

    when:
    Response response = studentService.getStudent("67")
    println "** Response "+response
    println "** Response "+response.getEntity()

    then:
    response != null
    }
}

When I Run the above code using maven clean install command, I am getting the following error.

Error :

    1*studentDao.getStudent(67) >>> new Student()   (0 invocations)

If I Use 0*studentDao.getStudent(67) >>> new Student() I am Getting response.getEntity() is null