linked-list: Rewrite tests to use hspec with fail-fast.

exercises/linked-list/package.yaml

@@ -17,4 +17,4 @@ tests:
     source-dirs: test
     dependencies:
       - linked-list
-      - HUnit
+      - hspec

exercises/linked-list/test/Tests.hs

@@ -1,57 +1,54 @@
-import Test.HUnit (Assertion, (@=?), runTestTT, Test(..), Counts(..))
-import System.Exit (ExitCode(..), exitWith)
--- Consider using Control.Concurrent.STM.TMVar or Control.Concurrent.MVar
--- to deal with the mutability
-import Deque (mkDeque, push, pop, shift, unshift)
+import Test.Hspec        (Spec, describe, it, shouldReturn)
+import Test.Hspec.Runner (configFastFail, defaultConfig, hspecWith)
 
-exitProperly :: IO Counts -> IO ()
-exitProperly m = do
-  counts <- m
-  exitWith $ if failures counts /= 0 || errors counts /= 0 then ExitFailure 1 else ExitSuccess
-
-testCase :: String -> Assertion -> Test
-testCase label assertion = TestLabel label (TestCase assertion)
+import Deque (mkDeque, pop, push, shift, unshift)
 
 main :: IO ()
-main = exitProperly $ runTestTT $ TestList
-  [ TestList dequeTests ]
-
-dequeTests :: [Test]
-dequeTests =
-  [ testCase "push pop" $ do
-    deque <- mkDeque
-    push deque 'a'
-    push deque 'b'
-    pop deque >>= (Just 'b' @=?)
-    pop deque >>= (Just 'a' @=?)
-  , testCase "push shift" $ do
-    deque <- mkDeque
-    push deque 'a'
-    push deque 'b'
-    shift deque >>= (Just 'a' @=?)
-    shift deque >>= (Just 'b' @=?)
-  , testCase "unshift shift" $ do
-    deque <- mkDeque
-    unshift deque 'a'
-    unshift deque 'b'
-    shift deque >>= (Just 'b' @=?)
-    shift deque >>= (Just 'a' @=?)
-  , testCase "unshift pop" $ do
-    deque <- mkDeque
-    unshift deque 'a'
-    unshift deque 'b'
-    pop deque >>= (Just 'a' @=?)
-    pop deque >>= (Just 'b' @=?)
-  , testCase "example" $ do
-    deque <- mkDeque
-    push deque 'a'
-    push deque 'b'
-    pop deque >>= (Just 'b' @=?)
-    push deque 'c'
-    shift deque >>= (Just 'a' @=?)
-    unshift deque 'd'
-    push deque 'e'
-    shift deque >>= (Just 'd' @=?)
-    pop deque >>= (Just 'e' @=?)
-    pop deque >>= (Just 'c' @=?)
-  ]
+main = hspecWith defaultConfig {configFastFail = True} specs
+
+specs :: Spec
+specs = describe "linked-list" $ do
+
+    -- As of 2016-08-10, there was no reference file
+    -- for the test cases in `exercism/x-common`.
+
+    it "push pop" $ do
+      deque <- mkDeque
+      push deque 'a'
+      push deque 'b'
+      pop deque `shouldReturn` Just 'b'
+      pop deque `shouldReturn` Just 'a'
+
+    it "push shift" $ do
+      deque <- mkDeque
+      push deque 'a'
+      push deque 'b'
+      shift deque `shouldReturn` Just 'a'
+      shift deque `shouldReturn` Just 'b'
+
+    it "unshift shift" $ do
+      deque <- mkDeque
+      unshift deque 'a'
+      unshift deque 'b'
+      shift deque `shouldReturn` Just 'b'
+      shift deque `shouldReturn` Just 'a'
+
+    it "unshift pop" $ do
+      deque <- mkDeque
+      unshift deque 'a'
+      unshift deque 'b'
+      pop deque `shouldReturn` Just 'a'
+      pop deque `shouldReturn` Just 'b'
+
+    it "example" $ do
+      deque <- mkDeque
+      push deque 'a'
+      push deque 'b'
+      pop deque `shouldReturn` Just 'b'
+      push deque 'c'
+      shift deque `shouldReturn` Just 'a'
+      unshift deque 'd'
+      push deque 'e'
+      shift deque `shouldReturn` Just 'd'
+      pop deque `shouldReturn` Just 'e'
+      pop deque `shouldReturn` Just 'c'