re-use an installed VM in /per-rule

Signed-off-by: Jiri Jaburek <[email protected]>

per-rule/test.py

@@ -85,12 +85,14 @@ def report_test_with_log(status, note, log_dir, rule_name, test_name):
 our_rules_textblock = textwrap.indent(('\n'.join(our_rules)), '    ')
 util.log(f"testing rules:\n{our_rules_textblock}")
 
-g = virt.Guest()
-
-# install a qcow2-backed VM, so automatus.py can snapshot it
-# - use hardening-style partitions, automatus tests need them
-ks = virt.Kickstart(partitions=partitions.partitions)
-g.install(kickstart=ks, disk_format='qcow2')
+# tag named after the tool that modifies the VM/image
+g = virt.Guest('automatus')
+
+if not g.is_installed():
+    # install a qcow2-backed VM, so automatus.py can snapshot it
+    # - use hardening-style partitions, automatus tests need them
+    ks = virt.Kickstart(partitions=partitions.partitions)
+    g.install(kickstart=ks, disk_format='qcow2')
 
 with util.get_content() as content_dir, g.booted():
     env = os.environ.copy()