question: public final TestSubscriber assertError ( Throwable error ) { String prefix = "" ; boolean passed = true ; if ( done . getCount ( ) != 0 ) { prefix = "Subscriber still running! " ; } int s = errors . size ( ) ; if ( s == 0 ) { fail ( prefix , "No errors" , Collections . < Throwable > emptyList ( ) ) ; passed = false ; } pass ( "error received" , passed ) ; return this ; }
target:  Assert that this TestSubscriber received exactly the specified onError event value.