Hello, I have following issue I have met second time now and I would like to ask you for an explanation and possibly for an advice. I am trying to migrate python-bitstruct and when I use %pytest instead of setup.py test I get following error: [ 7s] import bitstruct.c [ 7s] E ModuleNotFoundError: No module named 'bitstruct.c' In case I run %check %python_expand PYTHONPATH=%{buildroot}%{$python_sitearch} $python setup.py test %pytest_arch pytest_arch succedes. It boiled down that the reason is, for 3.6 for example: copying build/lib.linux-x86_64-3.6/bitstruct/c.cpython-36m-x86_64-linux-gnu.so -> bitstruct Note though, that bitstruct/c.cpython-36m-x86_64-linux-gnu.so is available to %pytest even if setup.py test is not called: $ file /home/abuild/rpmbuild/BUILDROOT/python-bitstruct-8.11.0-0.x86_64/usr/lib64/python3.6/site-packages/bitstruct/c.cpython-36m-x86_64-linux-gnu.so /home/abuild/rpmbuild/BUILDROOT/python-bitstruct-8.11.0-0.x86_64/usr/lib64/python3.6/site-packages/bitstruct/c.cpython-36m-x86_64-linux-gnu.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=98a2f9f5618416992f7d49c3980a2b2f83b4df6e, stripped $ But $ file _build.python36/lib.linux-x86_64-3.6/bitstruct/c.cpython-36m-x86_64-linux-gnu.so _build.python36/lib.linux-x86_64-3.6/bitstruct/c.cpython-36m-x86_64-linux-gnu.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=9a390d431fd0b0a8d895384da74f5324848f83cf, with debug_info, not stripped $ What I am missing? Petr -- Have a lot of fun!