Fix Void package acceptance gaps

tests/test_packaging.py

@@ -96,6 +96,21 @@ def _find_package(fmt: str) -> Path:
     return candidate
 
 
+def test_runit_logger_uses_accounts_shipped_by_package():
+    """The runit logger must use the package's group-only identity.
+
+    The package declares a ``fenris`` group for store/log access, not a
+    ``fenris`` service user.  Starting the logger with ``fenris:fenris``
+    therefore leaves the diagnostics supervisor down on a real Void host;
+    Void's standard ``nobody`` account supplies the unprivileged uid.
+    """
+    logger = (REPO_ROOT / "units" / "runit" / "fenris-collect" / "log" / "run").read_text()
+    sysusers = (REPO_ROOT / "packaging" / "sysusers.d" / "fenris.conf").read_text()
+
+    assert "g fenris -" in sysusers
+    assert "chpst -u nobody:fenris" in logger
+
+
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