what does >> and 1* means in this groovy statement?

I am working on grails/groovy project and while reading their test documentation came across this line of code

1 * myService.prova() >> { true }

I am unable to understand what does 1 * means here also as >> is right shift operator what does it mean here ? I have searched so much but unable to get any proper explanation. Grails Test Documenation