Forwarded: https://github.com/prody/ProDy/issues/1622
--- a/setup.py
+++ b/setup.py
@@ -82,6 +82,7 @@
     'prody.utilities': ['datafiles/*.dat'],
     'prody.tests': ['datafiles/pdb*.pdb',
                     'datafiles/*.dat',
+                    'datafiles/*.cif',
                     'datafiles/*.coo',
                     'datafiles/dcd*.dcd',
                     'datafiles/xml*.xml',