* guix/store/roots.scm (gc-roots): Wrap 'scandir*' call in 'catch'. * tests/store-roots.scm ("gc-roots, initial"): New test. Move 'open-connection' call below.
* guix/store/roots.scm, tests/store-roots.scm: New files. * Makefile.am (STORE_MODULES): Add guix/store/roots.scm. (SCM_TESTS): Add tests/store-roots.scm.