@jhpalmieri - thanks for digging this up. It's a name clash between (generated) conftest.py used in checking Sage's Python, and conftest.py introduced by this PR, and used by pytest. It's probably a standard name for pytest, so we'd need to rename conftest.py in the macros used by ./configure. I'll try to fix this. @tobiasdiez
Originally posted by @dimpase in #39206 (comment)