diff --git a/Stackage/Test.hs b/Stackage/Test.hs
index d6bcaf6f..80cd658f 100644
--- a/Stackage/Test.hs
+++ b/Stackage/Test.hs
@@ -1,19 +1,23 @@
+{-# LANGUAGE CPP #-}
 module Stackage.Test
     ( runTestSuites
     ) where
 
-import           Control.Monad    (foldM, unless, when)
-import qualified Data.Map         as Map
-import qualified Data.Set         as Set
+import           Control.Monad      (foldM, unless, when)
+import qualified Data.Map           as Map
+import qualified Data.Set           as Set
 import           Stackage.Config
 import           Stackage.Types
 import           Stackage.Util
-import           System.Directory (createDirectory, removeFile)
-import           System.Exit      (ExitCode (ExitSuccess))
-import           System.FilePath  ((<.>), (</>))
-import           System.IO        (IOMode (WriteMode, AppendMode),
-                                   withBinaryFile)
-import           System.Process   (runProcess, waitForProcess)
+import           System.Directory   (createDirectory, removeFile, canonicalizePath)
+import           System.Environment (getEnvironment)
+import           System.Exit        (ExitCode (ExitSuccess))
+import           System.FilePath    ((<.>), (</>))
+import           System.IO          (IOMode (WriteMode, AppendMode),
+                                     withBinaryFile)
+import           System.Process     (runProcess, waitForProcess)
+import Distribution.Text
+import Data.Maybe
 
 runTestSuites :: InstallInfo -> IO ()
 runTestSuites ii = do
@@ -23,30 +27,47 @@ runTestSuites ii = do
     allPass <- foldM (runTestSuite testdir) True $ Map.toList $ iiPackages ii
     unless allPass $ error $ "There were failures, please see the logs in " ++ testdir
 
+-- | Separate for the PATH environment variable
+pathSep :: Char
+#ifdef mingw32_HOST_OS
+pathSep = ';'
+#else
+pathSep = ':'
+#endif
+
+fixEnv :: FilePath -> (String, String) -> (String, String)
+fixEnv bin (p@"PATH", x) = (p, bin ++ pathSep : x)
+fixEnv _ x = x
+
 runTestSuite :: FilePath -> Bool -> (PackageName, Version) -> IO Bool
 runTestSuite testdir prevPassed pair@(packageName, _) = do
+    -- Set up a new environment that includes the cabal-dev/bin folder in PATH.
+    env' <- getEnvironment
+    bin <- canonicalizePath "cabal-dev/bin"
+    let menv = Just $ map (fixEnv bin) env'
+
     passed <- do
-        ph1 <- getHandle WriteMode $ \handle -> runProcess "cabal" ["unpack", package] (Just testdir) Nothing Nothing (Just handle) (Just handle)
+        ph1 <- getHandle WriteMode $ \handle -> runProcess "cabal" ["unpack", package] (Just testdir) menv Nothing (Just handle) (Just handle)
         ec1 <- waitForProcess ph1
         if (ec1 /= ExitSuccess)
             then return False
             else do
-                ph2 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["-s", "../../cabal-dev", "configure", "--enable-tests"] (Just dir) Nothing Nothing (Just handle) (Just handle)
+                ph2 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["-s", "../../cabal-dev", "configure", "--enable-tests"] (Just dir) menv Nothing (Just handle) (Just handle)
                 ec2 <- waitForProcess ph2
                 if (ec2 /= ExitSuccess)
                     then return False
                     else do
-                        ph3 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["build"] (Just dir) Nothing Nothing (Just handle) (Just handle)
+                        ph3 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["build"] (Just dir) menv Nothing (Just handle) (Just handle)
                         ec3 <- waitForProcess ph3
                         if (ec3 /= ExitSuccess)
                             then return False
                             else do
-                                ph4 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["test"] (Just dir) Nothing Nothing (Just handle) (Just handle)
+                                ph4 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["test"] (Just dir) menv Nothing (Just handle) (Just handle)
                                 ec4 <- waitForProcess ph4
                                 if (ec4 /= ExitSuccess)
                                     then return False
                                     else do
-                                        ph5 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["haddock"] (Just dir) Nothing Nothing (Just handle) (Just handle)
+                                        ph5 <- getHandle AppendMode $ \handle -> runProcess "cabal-dev" ["haddock"] (Just dir) menv Nothing (Just handle) (Just handle)
                                         ec5 <- waitForProcess ph5
                                         return $ ec5 == ExitSuccess
     let expectedFailure = packageName `Set.member` expectedFailures