Issue 423: absolutedate_to_datetime behaviour during leap second

This is a proposal to fix #423 (closed).

python_files/pyhelpers.py

@@ -104,13 +104,19 @@ def absolutedate_to_datetime(orekit_absolutedate):
     or_date = or_comp.getDate()
     or_time = or_comp.getTime()
     seconds = or_time.getSecond()
+    seconds_int = int(math.floor(seconds))
+    microseconds = int(1000000.0 * (seconds - math.floor(seconds)))
+    if seconds_int > 59:  # This can take the value 60 during a leap second
+        seconds_int = 59
+        microseconds = 999999  # Also modifying microseconds to ensure that the time flow stays monotonic
+
     return datetime(or_date.getYear(),
                     or_date.getMonth(),
                     or_date.getDay(),
                     or_time.getHour(),
                     or_time.getMinute(),
-                    int(math.floor(seconds)),
-                    int(1000000.0 * (seconds - math.floor(seconds))))
+                    seconds_int,
+                    microseconds)
 
 
 def datetime_to_absolutedate(dt_date):