Add remaining haskell book exercises

Haskell-book/14/morse/tests/tests.hs

@@ -0,0 +1,86 @@
+module Main where
+
+import qualified Data.Map as M
+import Morse
+import Test.QuickCheck
+import Test.QuickCheck.Gen (oneof)
+
+allowedChars :: [Char]
+allowedChars = M.keys letterToMorse
+
+allowedMorse :: [Morse]
+allowedMorse = M.elems letterToMorse
+
+charGen :: Gen Char
+charGen = elements allowedChars
+
+morseGen :: Gen Morse
+morseGen = elements allowedMorse
+
+prop_thereAndBackAgain :: Property
+prop_thereAndBackAgain =
+    forAll charGen (\c -> ((charToMorse c) >>= morseToChar) == Just c)
+
+main' :: IO ()
+main' = quickCheck prop_thereAndBackAgain
+
+data Trivial = Trivial deriving (Eq, Show)
+
+trivialGen :: Gen Trivial
+trivialGen = return Trivial
+
+instance Arbitrary Trivial where
+    arbitrary = trivialGen
+
+main :: IO ()
+main = do
+    sample trivialGen
+
+data Identity a = Identity a deriving (Eq, Show)
+
+identityGen :: Arbitrary a => Gen (Identity a)
+identityGen = do
+    a <- arbitrary
+    return (Identity a)
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = identityGen
+
+identityGenInt :: Gen (Identity Int)
+identityGenInt = identityGen
+
+data Pair a b = Pair a b deriving (Eq, Show)
+
+pairGen :: (Arbitrary a, Arbitrary b) => Gen (Pair a b)
+pairGen = do
+    a <- arbitrary
+    b <- arbitrary
+    return (Pair a b)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Pair a b) where
+    arbitrary = pairGen
+
+pairGenIntString :: Gen (Pair Int String)
+pairGenIntString = pairGen
+
+data Sum a b = First a | Second b deriving (Eq, Show)
+
+sumGenEqual :: Gen (Sum Char Int)
+sumGenEqual = do
+    a <- arbitrary
+    b <- arbitrary
+    oneof [return $ First a,
+           return $ Second b]
+
+sumGenCharInt :: Gen (Sum Char Int)
+sumGenCharInt = sumGenEqual
+
+sumGenFirstPls :: (Arbitrary a, Arbitrary b) => Gen (Sum a b)
+sumGenFirstPls = do
+    a <- arbitrary
+    b <- arbitrary
+    frequency [(10, return $ First a),
+               (1, return $ Second b)]
+
+sumGenCharIntFirst :: Gen (Sum Char Int)
+sumGenCharIntFirst = sumGenFirstPls