ENH use bracket dbus for xmobar tests

bin/xmobar.hs

@@ -46,7 +46,7 @@ main = getArgs >>= parse
 parse :: [String] -> IO ()
 parse [] = run
 parse ["--deps"] = withCache printDeps
-parse ["--test"] = void $ withCache . evalConfig =<< connectDBus
+parse ["--test"] = withCache $ withDBus_ evalConfig
 parse _ = usage
 
 run :: IO ()
@@ -66,11 +66,13 @@ evalConfig db = do
   return $ config bf ifs ios cs d
 
 printDeps :: FIO ()
-printDeps = do
-  db <- io connectDBus
-  let ps = sort $ nub $ fmap showFulfillment $ concatMap dumpFeature $ allFeatures db
-  io $ mapM_ (putStrLn . T.unpack) ps
-  io $ disconnectDBus db
+printDeps = withDBus_ $ \db ->
+  mapM_ (liftIO . putStrLn . T.unpack) $
+    sort $
+      nub $
+        fmap showFulfillment $
+          concatMap dumpFeature $
+            allFeatures db
 
 usage :: IO ()
 usage =