tests: quickfix flaky error message assertion

Every now and then this test fails, because pyca/cryptography
raises an unexpected error message (see pyca/cryptography#8563)

Regardless of whether it is a good idea to assert error messages of
3rd party libraries, this patch provides a quick fix by asserting
that is one of both known error messages.

closes secure-systems-lab#463

Signed-off-by: Lukas Puehringer <lukas.puehringer@nyu.edu>

tests/test_interface.py

@@ -276,13 +276,6 @@ def test_rsa(self):  # pylint: disable=too-many-locals,too-many-statements
                     CryptoError,
                     "Password was not given but private key is encrypted",
                 ),
-                # Error on encrypted but bad pw passed
-                (
-                    [fn_encrypted],
-                    {"password": "bad pw"},
-                    CryptoError,
-                    "Bad decrypt. Incorrect password?",
-                ),
                 # Error on pw and prompt
                 (
                     [fn_default],
@@ -307,6 +300,18 @@ def test_rsa(self):  # pylint: disable=too-many-locals,too-many-statements
                 ),
             )
 
+        # Error on encrypted but bad pw passed
+        # NOTE: for some key+pw combos the error differs, see pyca/cryptography#8563
+        with self.assertRaises(CryptoError) as ctx:
+            import_rsa_privatekey_from_file(fn_encrypted, password="bad pw")
+
+        error = str(ctx.exception)
+        self.assertTrue(
+            "Bad decrypt. Incorrect password?" in error
+            or "Could not deserialize key data" in error,
+            f"unexpected: {error}",
+        )
+
         # Error on encrypted but bad pw prompted
         err_msg = "Password was not given but private key is encrypted"
         with self.assertRaises(CryptoError) as ctx, mock.patch(