diff --git a/mangopay.cabal b/mangopay.cabal
--- a/mangopay.cabal
+++ b/mangopay.cabal
@@ -1,5 +1,5 @@
 name:           mangopay
-version:        1.9.4
+version:        1.9.5
 cabal-version:  >= 1.8
 build-type:     Simple
 author:         JP Moresmau <jpmoresmau@gmail.com>
@@ -56,6 +56,7 @@
      , country-codes        == 0.1.*
 
        -- Needed for TestUtils
+     , async                >= 2.0
      , blaze-builder
      , HUnit                >= 1.2.5
      , wai                  >= 3.0        && < 3.1
@@ -107,7 +108,7 @@
   main-is:         mangopay-tests.hs
   ghc-options:     -Wall -rtsopts -threaded
   build-depends:
-     base, aeson, attoparsec, base16-bytestring,
+     base, aeson, async, attoparsec, base16-bytestring,
      base64-bytestring, blaze-builder, bytestring,
      case-insensitive, conduit, data-default, http-conduit,
      http-types, HUnit, lifted-base, monad-control, monad-logger,
diff --git a/src/Web/MangoPay/TestUtils.hs b/src/Web/MangoPay/TestUtils.hs
--- a/src/Web/MangoPay/TestUtils.hs
+++ b/src/Web/MangoPay/TestUtils.hs
@@ -3,6 +3,7 @@
 module Web.MangoPay.TestUtils
   ( -- * Initialization
     withMangoPayTestUtils
+  , withMangoPayTestUtils'
 
     -- * Test helpers
   , testCardInfo1
@@ -28,7 +29,6 @@
 import Control.Monad.Logger (LoggingT, runStdoutLoggingT, logDebugS, logWarnS)
 import Control.Monad.Trans.Resource (ResourceT, runResourceT)
 import Data.Conduit (($$+-))
-import Data.Default (def)
 import Data.Maybe (isJust)
 import Data.Monoid ((<>))
 import Data.Text (Text)
@@ -41,6 +41,7 @@
 
 import Web.MangoPay
 
+import qualified Control.Concurrent.Async as AS
 import qualified Data.ByteString.Lazy as BSL
 import qualified Network.HTTP.Conduit as H
 import qualified Data.Aeson as A
@@ -245,7 +246,19 @@
      -- ^ Action to run while being able to use functions from
      -- this module.
   -> IO a
-withMangoPayTestUtils act =
+withMangoPayTestUtils = withMangoPayTestUtils' . const . const
+
+
+-- | Same as 'withMangoPayTestUtils', but also gives more
+-- information about the environment to the action.
+withMangoPayTestUtils'
+  :: (   Credentials
+      -> H.Manager
+      -> IO a )
+     -- ^ Action to run while being able to use functions from
+     -- this module.
+  -> IO a
+withMangoPayTestUtils' act =
   H.withManager $ \mgr -> liftIO $ do
     hook <- getHookEndPoint
     res  <- newReceivedEvents
@@ -257,7 +270,7 @@
     bracket
       (startHTTPServer hook res)
       killThread
-      (const $ initializeTestState >> act)
+      (const $ initializeTestState >>= flip act mgr)
 
 
 ----------------------------------------------------------------------
@@ -346,7 +359,7 @@
 -- (this file can be generated by mangopay-passphrase),
 -- generates a new id/name, keeps the same email and generates a new secret
 -- saves the secret to use in other tests.
-initializeTestState :: IO ()
+initializeTestState :: IO Credentials
 initializeTestState = do
   mgr <- getTestHttpManager
   creds <- createCredentials mgr
@@ -355,6 +368,7 @@
     ts { tsCredentials = creds
        , tsAccessToken = toAccessToken at }
   listenForAll
+  return creds
 
 
 -- | (Internal) Add the current time as a suffix to the client id
@@ -398,7 +412,7 @@
 
 -- | (Internal) Listen for all event types.
 listenForAll :: IO ()
-listenForAll = mapM_ listenFor [minBound .. maxBound]
+listenForAll = void $ AS.mapConcurrently listenFor [minBound .. maxBound]
 
 
 -- | (Internal) Create a hook for a given event type.