message: added sign check when creating a new timestamp from math operations.
diff: @@ -365,9 +365,9 @@ class TimeType(type_base.BaseType):
  a helper method that takes a float and sets a TimeType's seconds and useconds fields.
  Note: This method is private because it is only used by the _get_type_from_float helper to
  generate new TimeType instances. It is not meant to be used to modify an existing timestamp.
  - Note: Present implementation doesn't enforce that a TimeType be positive
  + Note: Present implementation will set any negative result to 0
  '''
  - # num = math.max(num, 0) # TODO decide behavior on whether to allow negative TimeStamps
  + num = max(num, 0)
  self.seconds = int(math.floor(num))
  self.useconds = int(round((num - self.seconds) * 1000000))
  