add DSA wycheproof tests (#4346)
diff --git a/tests/wycheproof/test_dsa.py b/tests/wycheproof/test_dsa.py
new file mode 100644
index 0000000..3dc3056
--- /dev/null
+++ b/tests/wycheproof/test_dsa.py
@@ -0,0 +1,49 @@
+# 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.
+
+from __future__ import absolute_import, division, print_function
+
+import binascii
+
+import pytest
+
+from cryptography.exceptions import InvalidSignature
+from cryptography.hazmat.backends.interfaces import DSABackend
+from cryptography.hazmat.primitives import hashes, serialization
+
+
+_DIGESTS = {
+ "SHA-1": hashes.SHA1(),
+ "SHA-224": hashes.SHA224(),
+ "SHA-256": hashes.SHA256(),
+}
+
+
+@pytest.mark.requires_backend_interface(interface=DSABackend)
+@pytest.mark.wycheproof_tests(
+ "dsa_test.json",
+)
+def test_dsa_signature(backend, wycheproof):
+ key = serialization.load_der_public_key(
+ binascii.unhexlify(wycheproof.testgroup["keyDer"]), backend
+ )
+ digest = _DIGESTS[wycheproof.testgroup["sha"]]
+
+ if (
+ wycheproof.valid or (
+ wycheproof.acceptable and not wycheproof.has_flag("NoLeadingZero")
+ )
+ ):
+ key.verify(
+ binascii.unhexlify(wycheproof.testcase["sig"]),
+ binascii.unhexlify(wycheproof.testcase["msg"]),
+ digest,
+ )
+ else:
+ with pytest.raises(InvalidSignature):
+ key.verify(
+ binascii.unhexlify(wycheproof.testcase["sig"]),
+ binascii.unhexlify(wycheproof.testcase["msg"]),
+ digest,
+ )