diff --git a/yesod-core/Yesod/Internal/Request.hs b/yesod-core/Yesod/Internal/Request.hs
index 43040b45..49c3be18 100644
--- a/yesod-core/Yesod/Internal/Request.hs
+++ b/yesod-core/Yesod/Internal/Request.hs
@@ -1,9 +1,14 @@
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP #-}
 module Yesod.Internal.Request
     ( parseWaiRequest
     , Request (..)
     , RequestBodyContents
     , FileInfo (..)
+#ifdef TEST
+    , randomString
+    , parseWaiRequest'
+#endif
     ) where
 
 import Control.Applicative ((<$>))
diff --git a/yesod-core/test/Test/InternalRequest.hs b/yesod-core/test/Test/InternalRequest.hs
new file mode 100644
index 00000000..215d467a
--- /dev/null
+++ b/yesod-core/test/Test/InternalRequest.hs
@@ -0,0 +1,89 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Test.InternalRequest where
+
+import Data.List (nub)
+import System.Random (StdGen, mkStdGen)
+import Control.Applicative ((<$>))
+
+import Blaze.ByteString.Builder
+
+import Yesod.Internal.Request
+import Network.Wai as W
+import Network.Wai.Test
+import Web.Cookie (renderCookies)
+import Test.Hspec
+import Test.Hspec.HUnit
+
+
+randomStringSpecs :: [Spec]
+randomStringSpecs = describe "Yesod.Internal.Request.randomString"
+  [ it "does not repeat itself" $ noRepeat 10 100
+  ]
+
+noRepeat len n = length (nub $ map (randomString len . mkStdGen) [1..n]) == n
+
+
+-- For convenience instead of "(undefined :: StdGen)".
+g :: StdGen
+g = undefined
+
+
+nonceSpecs :: [Spec]
+nonceSpecs = describe "Yesod.Internal.Request.parseWaiRequest (reqNonce)"
+  [ it "is Nothing for unsecure sessions" noUnsecureNonce
+  , it "ignores pre-existing nonce for unsecure sessions" ignoreUnsecureNonce
+  , it "uses preexisting nonce for secure sessions" useOldNonce
+  , it "generates a new nonce for secure sessions without nonce" generateNonce
+  ]
+
+noUnsecureNonce = reqNonce r == Nothing where
+  r = parseWaiRequest' defaultRequest [] Nothing g
+
+ignoreUnsecureNonce = reqNonce r == Nothing where
+  r = parseWaiRequest' defaultRequest [("_NONCE", "old")] Nothing g
+
+useOldNonce = reqNonce r == Just "old" where
+  r = parseWaiRequest' defaultRequest [("_NONCE", "old")] (Just undefined) g
+
+generateNonce = reqNonce r /= Nothing where
+  r = parseWaiRequest' defaultRequest [("_NONCE", "old")] (Just undefined) g
+
+
+langSpecs :: [Spec]
+langSpecs = describe "Yesod.Internal.Request.parseWaiRequest (reqLangs)"
+  [ it "respects Accept-Language" respectAcceptLang
+  , it "respects sessions" respectSessionLang
+  , it "respects cookies" respectCookieLang
+  , it "respects queries" respectQueryLang
+  , it "prioritizes correctly" prioritizeLangs
+  ]
+
+respectAcceptLang = reqLangs r == ["accept1", "accept2"] where
+  r = parseWaiRequest' defaultRequest
+        { requestHeaders = [("Accept-Language", "accept1, accept2")] } [] Nothing g
+
+respectSessionLang = reqLangs r == ["session"] where
+  r = parseWaiRequest' defaultRequest [("_LANG", "session")] Nothing g
+
+respectCookieLang = reqLangs r == ["cookie"] where
+  r = parseWaiRequest' defaultRequest
+        { requestHeaders = [("Cookie", toByteString $ renderCookies [("_LANG", "cookie")])]
+        } [] Nothing g
+
+respectQueryLang = reqLangs r == ["query"] where
+  r = parseWaiRequest' defaultRequest { queryString = [("_LANG", Just "query")] } [] Nothing g
+
+prioritizeLangs = reqLangs r == ["query", "cookie", "session", "accept1", "accept2"] where
+  r = parseWaiRequest' defaultRequest
+        { requestHeaders = [ ("Accept-Language", "accept1, accept2")
+                           , ("Cookie", toByteString $ renderCookies [("_LANG", "cookie")])
+                           ]
+        , queryString = [("_LANG", Just "query")]
+        } [("_LANG", "session")] Nothing g
+
+
+internalRequestTest :: [Spec]
+internalRequestTest = descriptions [ randomStringSpecs
+                                   , nonceSpecs
+                                   , langSpecs
+                                   ]