def test_caesar(self):
    self.assertEqual(caesar('ace', 'abcdef', 2), 'cea')
    self.assertEqual(caesar('cea', 'abcdef', (- 2)), 'ace')
    self.assertEqual(caesar('ace', 'abcdef', (- 2)), 'eac')
    self.assertEqual(caesar('eac', 'abcdef', 2), 'ace')
    self.assertEqual(caesar('ace', 'abcdef', 0), 'ace')
    self.assertEqual(caesar('xyz', 'abcdef', 2), 'xyz')
    self.assertEqual(caesar('abc', 'acegik', 2), 'ebg')
    self.assertEqual(caesar('ebg', 'acegik', (- 2)), 'abc')
def test_caesar(self):
    self.assertEqual(caesar('ace', 'abcdef', 2), 'cea')
    self.assertEqual(caesar('cea', 'abcdef', (- 2)), 'ace')
    self.assertEqual(caesar('ace', 'abcdef', (- 2)), 'eac')
    self.assertEqual(caesar('eac', 'abcdef', 2), 'ace')
    self.assertEqual(caesar('ace', 'abcdef', 0), 'ace')
    self.assertEqual(caesar('xyz', 'abcdef', 2), 'xyz')
    self.assertEqual(caesar('abc', 'acegik', 2), 'ebg')
    self.assertEqual(caesar('ebg', 'acegik', (- 2)), 'abc')