diff --git a/code/week05/src/Week05/Free.hs b/code/week05/src/Week05/Free.hs
index f5c8cb4..4904453 100644
--- a/code/week05/src/Week05/Free.hs
+++ b/code/week05/src/Week05/Free.hs
@@ -12,22 +12,25 @@
 
 module Week05.Free where
 
-import           Control.Monad        hiding (fmap)
-import           Data.Aeson           (ToJSON, FromJSON)
-import           Data.Text            (Text)
-import           Data.Void            (Void)
-import           GHC.Generics         (Generic)
-import           Plutus.Contract      hiding (when)
+import           Control.Monad              hiding (fmap)
+import           Control.Monad.Freer.Extras as Extras
+import           Data.Aeson                 (ToJSON, FromJSON)
+import           Data.Text                  (Text)
+import           Data.Void                  (Void)
+import           GHC.Generics               (Generic)
+import           Plutus.Contract            as Contract hiding (when)
+import           Plutus.Trace.Emulator      as Emulator
 import qualified PlutusTx
-import           PlutusTx.Prelude     hiding (Semigroup(..), unless)
-import           Ledger               hiding (singleton)
-import           Ledger.Constraints   as Constraints
-import qualified Ledger.Typed.Scripts as Scripts
-import           Ledger.Value         as Value
-import           Playground.Contract  (printJson, printSchemas, ensureKnownCurrencies, stage, ToSchema)
-import           Playground.TH        (mkKnownCurrencies, mkSchemaDefinitions)
-import           Playground.Types     (KnownCurrency (..))
-import           Text.Printf          (printf)
+import           PlutusTx.Prelude           hiding (Semigroup(..), unless)
+import           Ledger                     hiding (singleton)
+import           Ledger.Constraints         as Constraints
+import qualified Ledger.Typed.Scripts       as Scripts
+import           Ledger.Value               as Value
+import           Playground.Contract        (printJson, printSchemas, ensureKnownCurrencies, stage, ToSchema)
+import           Playground.TH              (mkKnownCurrencies, mkSchemaDefinitions)
+import           Playground.Types           (KnownCurrency (..))
+import           Text.Printf                (printf)
+import           Wallet.Emulator.Wallet
 
 {-# INLINABLE mkValidator #-}
 mkValidator :: ScriptContext -> Bool
@@ -55,7 +58,7 @@ mint mp = do
         tx      = Constraints.mustForgeValue val
     ledgerTx <- submitTxConstraintsWith @Void lookups tx
     void $ awaitTxConfirmed $ txId ledgerTx
-    logInfo @String $ printf "forged %s" (show val)
+    Contract.logInfo @String $ printf "forged %s" (show val)
 
 endpoints :: Contract () FreeSchema Text ()
 endpoints = mint' >> endpoints
@@ -65,3 +68,23 @@ endpoints = mint' >> endpoints
 mkSchemaDefinitions ''FreeSchema
 
 mkKnownCurrencies []
+
+test :: IO ()
+test = runEmulatorTraceIO $ do
+    let tn = "ABC"
+    h1 <- activateContractWallet (Wallet 1) endpoints
+    h2 <- activateContractWallet (Wallet 2) endpoints
+    callEndpoint @"mint" h1 $ MintParams
+        { mpTokenName = tn
+        , mpAmount    = 555
+        }
+    callEndpoint @"mint" h2 $ MintParams
+        { mpTokenName = tn
+        , mpAmount    = 444
+        }
+    void $ Emulator.waitNSlots 1
+    callEndpoint @"mint" h1 $ MintParams
+        { mpTokenName = tn
+        , mpAmount    = -222
+        }
+    void $ Emulator.waitNSlots 1