Deduplicate config file path calculation in test.

Author: athas

Cabal-tests/Cabal-tests.cabal

@@ -160,6 +160,7 @@ test-suite hackage-tests
     , bytestring
     , Cabal
     , Cabal-tree-diff
+    , cabal-install
     , containers
     , deepseq
     , directory

Cabal-tests/tests/HackageTests.hs

@@ -20,13 +20,12 @@ import Data.Foldable                               (traverse_)
 import Data.List                                   (isPrefixOf, isSuffixOf)
 import Data.Maybe                                  (mapMaybe)
 import Data.Monoid                                 (Sum (..))
+import Distribution.Client.Config                  (defaultConfigFile, defaultCacheDir)
 import Distribution.PackageDescription.Check       (PackageCheck (..), checkPackage)
 import Distribution.PackageDescription.PrettyPrint (showGenericPackageDescription)
 import Distribution.PackageDescription.Quirks      (patchQuirks)
 import Distribution.Simple.Utils                   (fromUTF8BS, toUTF8BS)
 import Numeric                                     (showFFloat)
-import System.Directory                            (getAppUserDataDirectory)
-import System.Environment                          (lookupEnv)
 import System.Exit                                 (exitFailure)
 import System.FilePath                             ((</>))
 
@@ -63,22 +62,15 @@ import Data.TreeDiff.Pretty          (ansiWlEditExprCompact)
 parseIndex :: (Monoid a, NFData a) => (FilePath -> Bool)
            -> (FilePath -> B.ByteString -> IO a) -> IO a
 parseIndex predicate action = do
-    cabalDir   <- getAppUserDataDirectory "cabal"
-    configPath <- getCabalConfigPath cabalDir
+    configPath <- defaultConfigFile
     cfg        <- B.readFile configPath
     cfgFields  <- either (fail . show) pure $ Parsec.readFields cfg
+    repoCache  <- case lookupInConfig "remote-repo-cache" cfgFields of
+                    []        -> defaultCacheDir   -- Default
+                    (rrc : _) -> return rrc        -- User-specified
     let repos        = reposFromConfig cfgFields
-        repoCache    = case lookupInConfig "remote-repo-cache" cfgFields of
-            []        -> cabalDir </> "packages"  -- Default
-            (rrc : _) -> rrc                      -- User-specified
         tarName repo = repoCache </> repo </> "01-index.tar"
     mconcat <$> traverse (parseIndex' predicate action . tarName) repos
-  where
-    getCabalConfigPath cabalDir = do
-        mx <- lookupEnv "CABAL_CONFIG"
-        case mx of
-            Just x  -> return x
-            Nothing -> return (cabalDir </> "config")
 
 
 parseIndex'