Without the change tests fails against `zlib-1.3` as:
def test_sanity(self, tmp_path):
# internal version number
> assert re.search(r"\d+\.\d+\.\d+(\.\d+)?$", features.version_codec("zlib"))
E AssertionError: assert None
E + where None = <function search at 0x7ffff74c5c60>('\\d+\\.\\d+\\.\\d+(\\.\\d+)?$', '1.3')
E + where <function search at 0x7ffff74c5c60> = re.search
E + and '1.3' = <function version_codec at 0x7ffff6896680>('zlib')
E + where <function version_codec at 0x7ffff6896680> = features.version_codec
Tests/test_file_png.py:82: AssertionError
Sergei Trofimovich
2f416c0e68