Added a benchmark for ChaCha20 AEAD (#7427)

Author: alex

tests/bench/__init__.py

@@ -0,0 +1,3 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.

tests/bench/test_aead.py

@@ -0,0 +1,18 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+import pytest
+
+from cryptography.hazmat.primitives.ciphers.aead import ChaCha20Poly1305
+
+from ..hazmat.primitives.test_aead import _aead_supported
+
+
+@pytest.mark.skipif(
+    not _aead_supported(ChaCha20Poly1305),
+    reason="Requires OpenSSL with ChaCha20Poly1305 support",
+)
+def test_chacha20poly1305(benchmark):
+    chacha = ChaCha20Poly1305(b"\x00" * 32)
+    benchmark(chacha.encrypt, b"\x00" * 12, b"hello world plaintext", b"")