Make sure we close DBs in Wallet Sqlite Specs

Instead of consuming 10s of GB, we the unit tests only consumes 50 MB at
most. Hopefully this will fix the CI unit test timeouts.

lib/core/test/unit/Cardano/Pool/DB/SqliteSpec.hs

@@ -14,51 +14,42 @@ module Cardano.Pool.DB.SqliteSpec
 import Prelude
 
 import Cardano.BM.Trace
-    ( traceInTVarIO )
+    ( nullTracer )
 import Cardano.DB.Sqlite
-    ( DBLog (..), SqliteContext )
+    ( DBLog (..) )
 import Cardano.Pool.DB
     ( DBLayer (..) )
 import Cardano.Pool.DB.Log
     ( PoolDbLog (..) )
 import Cardano.Pool.DB.Properties
     ( properties )
 import Cardano.Pool.DB.Sqlite
-    ( newDBLayer, withDBLayer )
+    ( withDBLayer )
 import Cardano.Wallet.DummyTarget.Primitive.Types
     ( dummyTimeInterpreter )
 import System.Directory
     ( copyFile )
 import System.FilePath
     ( (</>) )
 import Test.Hspec
-    ( Spec, before, describe, it, shouldBe )
+    ( Spec, around, describe, it, shouldBe )
 import Test.Hspec.Extra
     ( parallel )
 import Test.Utils.Paths
     ( getTestData )
 import Test.Utils.Trace
     ( captureLogging )
-import UnliftIO.STM
-    ( TVar, newTVarIO )
 import UnliftIO.Temporary
     ( withSystemTempDirectory )
 
--- | Set up a DBLayer for testing, with the command context, and the logging
--- variable.
-newMemoryDBLayer :: IO (DBLayer IO)
-newMemoryDBLayer = snd . snd <$> newMemoryDBLayer'
-
-newMemoryDBLayer' :: IO (TVar [PoolDbLog], (SqliteContext, DBLayer IO))
-newMemoryDBLayer' = do
-    logVar <- newTVarIO []
-    (logVar, ) <$> newDBLayer (traceInTVarIO logVar) Nothing ti
-  where
-    ti = dummyTimeInterpreter
+withMemoryDBLayer
+    :: (DBLayer IO -> IO a)
+    -> IO a
+withMemoryDBLayer = withDBLayer nullTracer Nothing dummyTimeInterpreter
 
 spec :: Spec
 spec = parallel $ do
-    before newMemoryDBLayer $ do
+    around withMemoryDBLayer $ do
         parallel $ describe "Sqlite" properties
 
     describe "Migration Regressions" $ do