refactor(tests): use datetime.datetime.now to fix DeprecationWarning and remain compatible with Python 3.10+

Author: antoineauger

tests/test_smime_signing.py

@@ -30,8 +30,10 @@ def generate_ca_certificate(
         .issuer_name(ca_name)
         .public_key(ca_public_key)
         .serial_number(x509.random_serial_number())
-        .not_valid_before(datetime.datetime.utcnow())
-        .not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=365))
+        .not_valid_before(datetime.datetime.now(datetime.timezone.utc))
+        .not_valid_after(
+            datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(days=365)
+        )
         .add_extension(
             x509.BasicConstraints(ca=True, path_length=None),
             critical=True,
@@ -81,8 +83,10 @@ def generate_intermediate_certificate(
         .issuer_name(ca_name)
         .public_key(intermediate_public_key)
         .serial_number(x509.random_serial_number())
-        .not_valid_before(datetime.datetime.utcnow())
-        .not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=365))
+        .not_valid_before(datetime.datetime.now(datetime.timezone.utc))
+        .not_valid_after(
+            datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(days=365)
+        )
         .add_extension(
             x509.BasicConstraints(ca=True, path_length=None),
             critical=True,
@@ -136,8 +140,10 @@ def generate_email_certificate(
         .issuer_name(intermediate_name)
         .public_key(email_public_key)
         .serial_number(x509.random_serial_number())
-        .not_valid_before(datetime.datetime.utcnow())
-        .not_valid_after(datetime.datetime.utcnow() + datetime.timedelta(days=365))
+        .not_valid_before(datetime.datetime.now(datetime.timezone.utc))
+        .not_valid_after(
+            datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(days=365)
+        )
         .add_extension(
             x509.BasicConstraints(ca=False, path_length=None),
             critical=True,