old_contents: import unittest 
  
  from datetime import date as vanilla_date, timedelta
  
  from calexicon.dates import 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))
  
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_equality(self):
          dd = DistantDate(2010, 8, 1)
          ProlepticJulianCalendar().bless(dd)
          dwc = DateWithCalendar(ProlepticJulianCalendar, DistantDate(2010, 8, 1)) 
          self.assertTrue(dwc == dd)
  
subject: Add a passing test for equality.