question: private void checkValidInterval ( Duration pollingInterval , int retries , long timeSleptMillis ) { long highSum = 0 ; long lowSum = 0 ; for ( int i = 0 ; i < retries ; i ++ ) { double currentInterval = pollingInterval . getMillis ( ) * Math . pow ( DataflowPipelineJob . DEFAULT_BACKOFF_EXPONENT , i ) ; double randomOffset = 0.5 * currentInterval ; highSum += Math . round ( currentInterval + randomOffset ) ; lowSum += Math . round ( currentInterval - randomOffset ) ; } assertThat ( timeSleptMillis , allOf ( greaterThanOrEqualTo ( lowSum ) , lessThanOrEqualTo ( highSum ) ) ) ; }
target:  Validates that a given time is valid for the total time slept by a AttemptBoundedExponentialBackOff given the number of retries and an initial polling interval.