Added test for get_signature_algorithm_from_private_key

Signed-off-by: kimbeelen <kbeelen@infiniot.nl>

Author: kimbeelen

test/test_signature_algorithms.py

@@ -0,0 +1,21 @@
+import pytest
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import rsa, dsa, ec, ed25519, ed448
+from openleadr.messaging import get_signature_algorithm_from_private_key
+
+
+@pytest.mark.parametrize("key, expected_alg", [
+    (rsa.generate_private_key(public_exponent=65537, key_size=2048), "rsa-sha256"),
+    (dsa.generate_private_key(key_size=2048), "dsa-sha256"),
+    (ec.generate_private_key(ec.SECP256R1()), "ecdsa-sha3-256"),
+    (ed25519.Ed25519PrivateKey.generate(), "rsa-sha256"),
+    (ed448.Ed448PrivateKey.generate(), "rsa-sha256"),
+])
+def test_key_type_sign_alg_match(key, expected_alg):
+    key_encoding = serialization.Encoding.PEM
+    key_format = serialization.PrivateFormat.PKCS8
+    key_encryption_alg = serialization.NoEncryption()
+    key_bytes = key.private_bytes(key_encoding, key_format, key_encryption_alg)
+    detected_alg = get_signature_algorithm_from_private_key(key_bytes)
+
+    assert detected_alg == expected_alg, f"Expected {expected_alg} but got {detected_alg}"