def test_sample1(self): s = "abca" self.assertEqual(palindrome(s), "aba")
def test_medium6(self): s = "ghgaxybtltcmdinnefuvjegkodpcwozbzqqarjj" self.assertEqual(palindrome(s), "abcdefedcba")
def test_medium7(self): s = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz" self.assertEqual(palindrome(s), "aba")
def test_medium3(self): s = "jqwerqpqoiwewqs" self.assertEqual(palindrome(s), "qweqpqewq")
def test_medium4(self): s = "yzaghbicjkdlefmnopeqdrsctbuvawx" self.assertEqual(palindrome(s), "abcdefedcba")
def test_medium1(self): s = "slatkor zarepyo tqenet opera rotas" self.assertEqual(palindrome(s), "sator arepo tenet opera rotas")
def test_medium2(self): s = "abbazfghijklmza" self.assertEqual(palindrome(s), "azfza")
def test_small2(self): s = "abacabazzzzzzzz" self.assertEqual(palindrome(s), "zzzzzzzz")
def test_trivial3(self): s = "abacabadabacaba" self.assertEqual(palindrome(s), "abacabadabacaba")
def test_trivial2(self): s = "ab" self.assertEqual(palindrome(s), "a")
def test_empty(self): s = "" self.assertEqual(palindrome(s), "")
def test_sample2(self): s = "babcad" self.assertEqual(palindrome(s), "bab")