Add unit tests

free-foil-hm.cabal

@@ -111,5 +111,31 @@ test-suite doctests
     , bifunctors
     , containers
     , doctest-parallel
-    , free-foil
+    , free-foil >=0.0.3
+    , free-foil-hm
+  default-language: Haskell2010
+
+test-suite spec
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      HM.InterpretSpec
+      Paths_free_foil_hm
+  hs-source-dirs:
+      test
+  ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
+  build-tools:
+      alex >=3.2.4
+    , happy >=1.19.9
+  build-tool-depends:
+      BNFC:bnfc >=2.9.4.1
+  build-depends:
+      array >=0.5.3.0
+    , base >=4.7 && <5
+    , bifunctors
+    , containers
+    , free-foil >=0.0.3
+    , free-foil-hm
+    , hspec
+    , hspec-discover
   default-language: Haskell2010

package.yaml

@@ -76,5 +76,17 @@ tests:
     main: Main.hs
     other-modules: []
     dependencies:
-      - free-foil
+      - free-foil-hm
       - doctest-parallel
+
+  spec:
+    main: Spec.hs
+    source-dirs: test
+    ghc-options:
+      - -threaded
+      - -rtsopts
+      - -with-rtsopts=-N
+    dependencies:
+      - free-foil-hm
+      - hspec
+      - hspec-discover

src/HM/Interpret.hs

@@ -1,19 +1,21 @@
 module HM.Interpret where
 
-import Control.Monad.Foil (emptyNameMap, emptyScope)
-import HM.Eval
-import HM.Parser.Par
-import HM.Syntax (toExpClosed)
-import HM.Typecheck
+import           Control.Monad.Foil (emptyNameMap, emptyScope)
+import           HM.Eval
+import           HM.Parser.Par
+import           HM.Syntax          (toExpClosed)
+import           HM.Typecheck
 
 data Result
   = Success String -- Output of evaluation.
   | Failure ErrorKind String -- Error kind with message.
+  deriving (Show)
 
 data ErrorKind
   = ParsingError
   | TypecheckingError
   | EvaluationError
+  deriving (Show)
 
 interpret :: String -> Result
 interpret input =
@@ -22,7 +24,7 @@ interpret input =
     Right e -> case inferType emptyNameMap e of
       Left err -> Failure TypecheckingError ("Typechecking error: " ++ err)
       Right _type -> case eval emptyScope e of
-        Left err -> Failure EvaluationError ("Evaluation error: " ++ err)
+        Left err     -> Failure EvaluationError ("Evaluation error: " ++ err)
         Right outExp -> Success (show outExp)
   where
     tokens = myLexer input

test/HM/InterpretSpec.hs

@@ -0,0 +1,32 @@
+module HM.InterpretSpec where
+
+import           Test.Hspec
+import Control.Monad (forM_)
+import           HM.Interpret
+
+isSuccess :: Result -> Bool
+isSuccess Success{} = True
+isSuccess _ = False
+
+isTypeError :: Result -> Bool
+isTypeError (Failure TypecheckingError _) = True
+isTypeError _ = False
+
+wellTypedPaths :: [FilePath]
+wellTypedPaths = ["well-typed/1.lam", "well-typed/2.lam"]
+
+illTypedPaths :: [FilePath]
+illTypedPaths = ["ill-typed/1.lam", "ill-typed/2.lam"]
+
+spec :: Spec
+spec = do
+
+  describe "well-typed expressions" $ do
+    forM_ wellTypedPaths $ \path -> it path $ do
+      contents <- readFile ("test/files/" ++ path)
+      interpret contents `shouldSatisfy` isSuccess
+
+  describe "ill-typed expressions" $ do
+    forM_ illTypedPaths $ \path -> it path $ do
+      contents <- readFile ("test/files/" ++ path)
+      interpret contents `shouldSatisfy` isTypeError

test/Spec.hs

@@ -0,0 +1 @@
+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}

test/files/ill-typed/2.lam

@@ -1 +1 @@
-let x = true in (if iszero x then 1 else 0)
+let x = true in (if iszero(x) then 1 else 0)