restic: change service type from simple to oneshot

Fixes #6930

modules/services/restic.nix

@@ -397,7 +397,7 @@ in
 
         Service =
           {
-            Type = "simple";
+            Type = "oneshot";
 
             X-RestartIfChanged = true;
             RuntimeDirectory = serviceName;

tests/integration/standalone/restic-home.nix

@@ -106,6 +106,19 @@ in
           "--keep-hourly 3"
         ];
       };
+
+      prune-opts = {
+        inherit passwordFile paths exclude;
+        initialize = true;
+        repository = "/home/alice/repos/prune-opts";
+        pruneOpts = [
+          "--keep-yearly 4"
+          "--keep-monthly 3"
+          "--keep-weekly 2"
+          "--keep-daily 2"
+          "--keep-hourly 3"
+        ];
+      };
     };
   };
 }

tests/integration/standalone/restic.nix

@@ -268,6 +268,9 @@ in
       assert int(actual) == 8, \
         f"Expected a snapshot count of 8 but got {actual}"
 
+    with subtest("Prune opts"):
+      systemctl_succeed_as_alice("start restic-backups-prune-opts.service")
+
     logout_alice()
   '';
 }