add tests to verify der/asn1 conversions

Author: mattsb42-aws

tests/algorithms/test_EC.py

@@ -31,6 +31,18 @@
 -----END EC PRIVATE KEY-----
 """
 
+# ES256 signatures generated to test conversion logic
+DER_SIGNATURE = (
+    b"0F\x02!\x00\x89yG\x81W\x01\x11\x9b0\x08\xa4\xd0\xe3g([\x07\xb5\x01\xb3"
+    b"\x9d\xdf \xd1\xbc\xedK\x01\x87:}\xf2\x02!\x00\xb2shTA\x00\x1a\x13~\xba"
+    b"J\xdb\xeem\x12\x1e\xfeMO\x04\xb2[\x86A\xbd\xc6hu\x953X\x1e"
+)
+ASN1_SIGNATURE = (
+    b"\x89yG\x81W\x01\x11\x9b0\x08\xa4\xd0\xe3g([\x07\xb5\x01\xb3\x9d\xdf "
+    b"\xd1\xbc\xedK\x01\x87:}\xf2\xb2shTA\x00\x1a\x13~\xbaJ\xdb\xeem\x12\x1e"
+    b"\xfeMO\x04\xb2[\x86A\xbd\xc6hu\x953X\x1e"
+)
+
 
 def _backend_exception_types():
     """Build the backend exception types based on available backends."""
@@ -51,6 +63,20 @@ def test_key_from_ecdsa():
     assert not ECKey(key, ALGORITHMS.ES256).is_public()
 
 
+@pytest.mark.cryptography
+@pytest.mark.skipif(CryptographyECKey is None, reason="pyca/cryptography backend not available")
+def test_cryptograhy_der_to_asn1():
+    key = CryptographyECKey(private_key, ALGORITHMS.ES256)
+    assert key._der_to_asn1(DER_SIGNATURE) == ASN1_SIGNATURE
+
+
+@pytest.mark.cryptography
+@pytest.mark.skipif(CryptographyECKey is None, reason="pyca/cryptography backend not available")
+def test_cryptograhy_asn1_to_der():
+    key = CryptographyECKey(private_key, ALGORITHMS.ES256)
+    assert key._asn1_to_der(ASN1_SIGNATURE) == DER_SIGNATURE
+
+
 class TestECAlgorithm:
 
     def test_key_from_pem(self):