old_contents: import unittest 
  
  from datetime import date as vanilla_date, timedelta
  
  from calexicon.calendars import ProlepticJulianCalendar
  from calexicon.dates import DateWithCalendar, DistantDate
  
  class TestDistantDate(unittest.TestCase):
      def test_subtraction(self):
          dd = DistantDate(10000, 1, 1)
          self.assertIsInstance(dd - vanilla_date(9999, 1, 1), timedelta)
          self.assertIsInstance(dd - timedelta(0), DistantDate)
  
      def test_subtract_correct_result(self):
          dd = DistantDate(10000, 1, 2)
          dd2 = DistantDate(10000, 1, 1)
          self.assertEqual(dd - dd2, timedelta(days=1))
  
      def test_subtract_vanilla_date_from_distant_date(self):
          dd = DistantDate(10000, 1, 2)
          d = vanilla_date(9984, 2, 29)
          x = 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31 + 15 * 365 + 3 + 2
          self.assertEqual(dd - d, timedelta(days=x))
  
      def test_subtract_early_vanilla_date(self):
          dd = DistantDate(10000, 2, 12)
          d = vanilla_date(1, 1, 1)
          x = vanilla_date(9999, 12, 31) - vanilla_date(1, 1, 1) + timedelta(days=43)
          self.assertEqual(dd - d, x)
  
      def test_subtract_two_distant_dates(self):
          dd = DistantDate(10000, 2, 12)
          dd2 = DistantDate(10000, 1, 1)
          self.assertEqual(dd - dd2, timedelta(days=42))
  
      def test_equality(self):
          dd = DistantDate(2010, 8, 1)
          ProlepticJulianCalendar().bless(dd)
          dwc = DateWithCalendar(ProlepticJulianCalendar, DistantDate(2010, 8, 1)) 
          self.assertTrue(dwc == dd)
  
      def test_equality_2(self):
          dd = DistantDate(2010, 8, 1)
          ProlepticJulianCalendar().bless(dd)
          dwc = DateWithCalendar(ProlepticJulianCalendar, DistantDate(2010, 8, 1)) 
          self.assertTrue(dd == dwc)
  
      def test_equality_of_two_distant_dates(self):
          d1 = DistantDate(2010, 8, 1)
          d2 = DistantDate(2010, 8, 1)
          self.assertTrue(d1 == d2)
  
      def test_julian_to_gregorian(self):
          self.assertEqual(DistantDate.julian_to_gregorian(9999, 12, 1), (10000, 2, 12))
  
new_contents: import unittest 
  
  from datetime import date as vanilla_date, timedelta
  
  from calexicon.calendars import ProlepticJulianCalendar
  from calexicon.dates import DateWithCalendar, DistantDate
  
  class TestDistantDate(unittest.TestCase):
      def test_subtraction(self):
          dd = DistantDate(10000, 1, 1)
          self.assertIsInstance(dd - vanilla_date(9999, 1, 1), timedelta)
          self.assertIsInstance(dd - timedelta(0), DistantDate)
  
      def test_subtract_correct_result(self):
          dd = DistantDate(10000, 1, 2)
          dd2 = DistantDate(10000, 1, 1)
          self.assertEqual(dd - dd2, timedelta(days=1))
  
      def test_subtract_vanilla_date_from_distant_date(self):
          dd = DistantDate(10000, 1, 2)
          d = vanilla_date(9984, 2, 29)
          x = 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31 + 15 * 365 + 3 + 2
          self.assertEqual(dd - d, timedelta(days=x))
  
      def test_subtract_early_vanilla_date(self):
          dd = DistantDate(10000, 2, 12)
          d = vanilla_date(1, 1, 1)
          x = vanilla_date(9999, 12, 31) - vanilla_date(1, 1, 1) + timedelta(days=43)
          self.assertEqual(dd - d, x)
  
      def test_subtract_two_distant_dates(self):
          dd = DistantDate(10000, 2, 12)
          dd2 = DistantDate(10000, 1, 1)
          self.assertEqual(dd - dd2, timedelta(days=42))
  
      def test_addition(self):
          dd = DistantDate(10000, 1, 1)
          td = timedelta(days=1)
          self.assertEqual(dd + td, DistantDate(10000, 1, 2))
      def test_equality(self):
          dd = DistantDate(2010, 8, 1)
          ProlepticJulianCalendar().bless(dd)
          dwc = DateWithCalendar(ProlepticJulianCalendar, DistantDate(2010, 8, 1)) 
          self.assertTrue(dwc == dd)
  
      def test_equality_2(self):
          dd = DistantDate(2010, 8, 1)
          ProlepticJulianCalendar().bless(dd)
          dwc = DateWithCalendar(ProlepticJulianCalendar, DistantDate(2010, 8, 1)) 
          self.assertTrue(dd == dwc)
  
      def test_equality_of_two_distant_dates(self):
          d1 = DistantDate(2010, 8, 1)
          d2 = DistantDate(2010, 8, 1)
          self.assertTrue(d1 == d2)
  
      def test_julian_to_gregorian(self):
          self.assertEqual(DistantDate.julian_to_gregorian(9999, 12, 1), (10000, 2, 12))
  
subject: Add a test for adding a timedelta to a DistantDate.