def test_noNewlineOpaque(self):
        """
        L{DigestCredentialFactory._generateOpaque} returns a value without
        newlines, regardless of the length of the nonce.
        """
        opaque = self.credentialFactory._generateOpaque(
            b"long nonce " * 10, None)
        self.assertNotIn(b'\n', opaque)

        L{DigestCredentialFactory._generateOpaque} returns a value without
        newlines, regardless of the length of the nonce.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/cred/test/test_digestauth.py