new_contents: #!/Library/FrameWorks/Python.framework/Versions/3.5/bin/python3
  
  from balance import TransactionManager
  from balance import Transaction
  import os
  import unittest
  
  
  class TestTransaction(unittest.TestCase):
      def test_constructor_positive_simple(self):
          t = Transaction(100, [])
          self.assertEqual(t.is_negative, False)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 0)
  
      def test_constructor_negative_simple(self):
          t = Transaction(-100, [])
          self.assertEqual(t.is_negative, True)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 0)
  
      def test_constructor_positive_small(self):
          t = Transaction(100.01, [])
          self.assertEqual(t.is_negative, False)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 1)
  
      def test_constructor_positive_big(self):
          t = Transaction(100.99, [])
          self.assertEqual(t.is_negative, False)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 99)
  
      def test_constructor_negative_small(self):
          t = Transaction(-100.99, [])
          self.assertEqual(t.is_negative, True)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 99)
  
      def test_constructor_negative_big(self):
          t = Transaction(-100.01, [])
          self.assertEqual(t.is_negative, True)
          self.assertEqual(t.dollars, 100)
          self.assertEqual(t.cents, 1)
  
      def test_string_positive_simple(self):
          t = Transaction(100.01, [])
          t.date = t.date.replace(1995, 12, 12)
          self.assertEqual(str(t), "100.01 on 1995-12-12")
  
      def test_string_negative_simple(self):
          t = Transaction(-100.01, [])
          t.date = t.date.replace(1995, 12, 12)
          self.assertEqual(str(t), "-100.01 on 1995-12-12")
  
      def test_string_complex(self):
          t = Transaction(100, ["birthday", "toy"])
          t.date = t.date.replace(1995, 12, 12)
          self.assertEqual(str(t), "100.00 on 1995-12-12 #birthday #toy")
  
  
  class TestTransactionManager(unittest.TestCase):
      pass
  
  
  if __name__ == "__main__":
      unittest.main()
  
subject: Add tests