Add 'test' command for running QuickCheck props

Language/Haskell/GhcMod/Test.hs

@@ -0,0 +1,43 @@
+module Language.Haskell.GhcMod.Test where
+
+import Data.List
+import System.FilePath
+import System.Directory
+
+import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.Monad
+import Language.Haskell.GhcMod.DynFlags
+
+import GHC  --(ModSummary(..), ModLocation(..), moduleName, findModule)
+import GHC.Exception
+import OccName
+
+test :: IOish m
+      => FilePath -> GhcModT m String
+test f = runGmlT' [Left f] (return . setHscInterpreted) $ do
+    mg <- getModuleGraph
+    root <- cradleRootDir <$> cradle
+    f' <- makeRelative root <$> liftIO (canonicalizePath f)
+    let Just ms = find ((==Just f') . ml_hs_file . ms_location) mg
+        mdl = ms_mod ms
+        mn = moduleName mdl
+
+    Just mi <- getModuleInfo mdl
+    let exs = map (occNameString . getOccName) $ modInfoExports mi
+        cqs = filter ("prop_" `isPrefixOf`) exs
+
+    setContext [ IIDecl $ simpleImportDecl mn
+               , IIDecl $ simpleImportDecl $ mkModuleName "Test.QuickCheck"
+               ]
+
+    _res <- mapM runTest cqs
+
+    return ""
+
+runTest :: GhcMonad m => String -> m (Maybe SomeException)
+runTest fn = do
+  res <- runStmt ("quickCheck " ++ fn) RunToCompletion
+  return $ case res of
+    RunOk [] -> Nothing
+    RunException se -> Just se
+    _ -> error "runTest"