question: public final TestSubscriber assertNotSubscribed ( ) { String prefix = "" ; if ( done . getCount ( ) != 0 ) { prefix = "Subscriber still running! " ; } if ( subscription . get ( ) != null ) { fail ( prefix , "Subscribed!" , errors ) ; } else if ( ! errors . isEmpty ( ) ) { fail ( prefix , "Not subscribed but errors found" , errors ) ; } return this ; }
target:  Assert that the onSubscribe method hasn't been called at all.