def test_encrypt_special_character(self):
encrypted = encrypt("Hello World!", 2)
self.assertEquals(encrypted, "jgnnq yqtnf!")
def test_encrypt_empty(self):
encrypted = encrypt("", 1)
self.assertEqual(encrypted, "")
def test_encrypt_with_key(self):
encrypted = encrypt("Hello World", 2)
self.assertEquals(encrypted, "jgnnq yqtnf")