fix: More tests

Author: tmathern

tests/test_unit_tests.py

@@ -1095,6 +1095,8 @@ def test_sign_file_callback_signer_reports_error(self):
 
             # Define a callback that always returns None to simulate an error
             def error_callback_signer(data: bytes) -> bytes:
+                # Could alternatively also raise an error
+                # raise RuntimeError("Simulated signing error")
                 return None
 
             # Create signer with error callback using create_signer function