def METHOD_NAME(self):
    """Test wether message is encrypted using and can be decrypted."""
    # encryption
    test_message = b"this is a test message"
    key, encrypted_message = symmetric_encrypt(test_message)
    self.assertNotEqual(test_message, encrypted_message)
    # decryption
    fernet = Fernet(key)
    decrypted_message = fernet.decrypt(encrypted_message)
    self.assertEqual(decrypted_message, test_message)