diff --git a/test/doctests.hs b/test/doctests.hs
index 6659d8c..97deb64 100644
--- a/test/doctests.hs
+++ b/test/doctests.hs
@@ -2,16 +2,20 @@
 module Main where
 
 import Test.DocTest
+import System.Environment
+import Data.Maybe
 
 main :: IO ()
-main = doctest
-  [ "-package", "ghc-" ++ VERSION_ghc
-  , "-package", "transformers-" ++ VERSION_transformers
-  , "-package", "mtl-" ++ VERSION_mtl
-  , "-package", "directory-" ++ VERSION_directory
-  , "-XScopedTypeVariables", "-XRecordWildCards", "-XNamedFieldPuns", "-XConstraintKinds", "-XFlexibleContexts", "-XDataKinds", "-XKindSignatures", "-XTypeOperators", "-XViewPatterns"
-  , "-idist/build/autogen/"
-  , "-optP-include"
-  , "-optPdist/build/autogen/cabal_macros.h"
-  , "Language/Haskell/GhcMod.hs"
-  ]
+main = do
+  distdir <- (fromMaybe "dist" . lookup "DOCTEST_DIST_DIR") `fmap` getEnvironment
+  doctest
+     [ "-package", "ghc-" ++ VERSION_ghc
+     , "-package", "transformers-" ++ VERSION_transformers
+     , "-package", "mtl-" ++ VERSION_mtl
+     , "-package", "directory-" ++ VERSION_directory
+     , "-XScopedTypeVariables", "-XRecordWildCards", "-XNamedFieldPuns", "-XConstraintKinds", "-XFlexibleContexts", "-XDataKinds", "-XKindSignatures", "-XTypeOperators", "-XViewPatterns"
+     , "-i" ++ distdir ++ "/build/autogen/"
+     , "-optP-include"
+     , "-optP" ++ distdir ++ "/build/autogen/cabal_macros.h"
+     , "Language/Haskell/GhcMod.hs"
+     ]