old_contents: from datetime import date as vanilla_date
  
  from calendar_testing import CalendarTest
  
  from calexicon.calendars.other import JulianDayNumber
  
  class TestJulianDayNumber(CalendarTest):
      def setUp(self):
          self.calendar = JulianDayNumber()
  
      def test_make_date(self):
          vd = vanilla_date(2010, 8, 1)
          d = self.calendar.from_date(vd)
          self.assertIsNotNone(d)
  
      def test_first_date(self):
          vd = vanilla_date(1, 1, 1)
          d = self.calendar.from_date(vd)
          self.assertEqual(str(d), 'Day 1721423 (Julian Day Number)')
  
      def compare_date_and_number(self, year, month, day, number):
          vd = vanilla_date(year, month, day)
          d = self.calendar.from_date(vd)
          self.assertEqual(d.native_representation(), {'day_number': number})
  
      def test_other_date(self):
          self.compare_date_and_number(2013, 1, 1, 2456293)
  
new_contents: from datetime import date as vanilla_date
  
  from calendar_testing import CalendarTest
  
  from calexicon.calendars.other import JulianDayNumber
  
  class TestJulianDayNumber(CalendarTest):
      def setUp(self):
          self.calendar = JulianDayNumber()
  
      def test_make_date(self):
          vd = vanilla_date(2010, 8, 1)
          d = self.calendar.from_date(vd)
          self.assertIsNotNone(d)
  
      def test_first_date(self):
          vd = vanilla_date(1, 1, 1)
          d = self.calendar.from_date(vd)
          self.assertEqual(str(d), 'Day 1721423 (Julian Day Number)')
  
      def compare_date_and_number(self, year, month, day, number):
          vd = vanilla_date(year, month, day)
          d = self.calendar.from_date(vd)
          self.assertEqual(d.native_representation(), {'day_number': number})
  
      def test_every_400_years(self):
          days_in_400_years = 400 * 365 + 97
          for i in range(25):
              self.compare_date_and_number(1 + 400 * i, 1, 1, 1721423 + days_in_400_years * i)
  
      def test_another_date(self):
          self.compare_date_and_number(2013, 1, 1, 2456293)
  
subject: Add a test to check the right number of days in 400 year cycles.