question: public static String randomSkewedDate ( ) { return String . format ( Locale . ROOT , "2010-10-31T10:31:%02d.000Z" , TestUtil . nextInt ( random ( ) , 0 , 59 ) ) ; }
target:  Returns a Date such that all results from this method always have the same values for  year+month+day+hour+minute but the seconds are randomized.  This can be helpful for  indexing documents with random date values that are biased for a narrow window  (one day) to test collisions/overlaps