sources: skip librepo test if no librepo can be imported

The librepo test has a similar issue as the dnf tests, we need
to use the system packages, c.f.
osbuild/containers#79

But ensure it is run as part of the unittests_as_user_smoke.

.github/workflows/test.yml

@@ -86,7 +86,7 @@ jobs:
       # The test_host.py:test_signals_on_separate_fd runs itself but that
       # run will happen without the tox env so a pip/tox installed pytest
       # will not be found, install the pytest package as a workaround
-    - run: sudo apt install -y tox python3-pytest
+    - run: sudo apt install -y tox python3-pytest python3-librepo
     - name: "Run as user on default runer"
       # Run with -n 16 as depsolve tests tend to be slow but fast when
       # parallized, the runtime is around 1-2min with this setup.

sources/test/test_librepo.py

@@ -1,7 +1,11 @@
 #!/usr/bin/python3
 from unittest.mock import patch
 
-import librepo
+try:
+    import librepo
+except ImportError:
+    import pytest
+    pytest.skip("need librepo to run this test")
 import pytest
 
 from osbuild import testutil