This test program dynamically adds a one nanosecond time shift every time the user hits ctrl+C. You need to do kill -9 to stop the program ;) Here is an example session ./lal_checktimestamps_test_01.py
src (00:00:05): 5 seconds
src (00:00:10): 10 seconds
^Cshifting by 1 ns
lal_checktimestamps+lal_checktimestamps0: discontinuity: timestamp = 12.000682382 s, offset = 24576; would have been 12.000682381 s, offset = 24576
src (00:00:15): 15 seconds
^Cshifting by 2 ns
lal_checktimestamps+lal_checktimestamps0: discontinuity: timestamp = 17.000682383 s, offset = 34816; would have been 17.000682382 s, offset = 34816
src (00:00:20): 20 seconds
^Cshifting by 3 ns
lal_checktimestamps+lal_checktimestamps0: discontinuity: timestamp = 22.000682384 s, offset = 45056; would have been 22.000682383 s, offset = 45056
^Z