From 98329e0a3dd4f78b5d815ac3896272ec70904901 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Thu, 11 Dec 2025 10:28:11 +0100
Subject: Add remaining haskell book exercises

---
 Haskell-book/16/func/test/Spec.hs | 54 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Haskell-book/16/func/test/Spec.hs

(limited to 'Haskell-book/16/func/test/Spec.hs')

diff --git a/Haskell-book/16/func/test/Spec.hs b/Haskell-book/16/func/test/Spec.hs
new file mode 100644
index 0000000..14de325
--- /dev/null
+++ b/Haskell-book/16/func/test/Spec.hs
@@ -0,0 +1,54 @@
+{-# LANGUAGE ViewPatterns #-}
+
+import Func
+import Test.QuickCheck
+import Test.QuickCheck.Function
+
+functorIdentity :: (Functor f, Eq (f a)) => f a -> Bool
+functorIdentity f = fmap id f == f
+
+functorCompose :: (Eq (f c), Functor f) =>
+       (a -> b)
+    -> (b -> c)
+    -> f a
+    -> Bool
+functorCompose f g x =
+    (fmap g (fmap f x)) == (fmap (g . f) x)
+
+functorCompose' :: (Eq (f c), Functor f) =>
+        f a
+    -> Fun a b
+    -> Fun b c
+    -> Bool
+functorCompose' x (Fun _ f) (Fun _ g) =
+    (fmap (g . f) x) == (fmap g . fmap f $ x)
+
+main :: IO ()
+main = do
+    quickCheck (functorIdentity :: Identity Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Identity Int -> Bool)
+    quickCheck (functorCompose' :: Identity Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Pair Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Pair Int -> Bool)
+    quickCheck (functorCompose' :: Pair Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Two Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Two Int Int -> Bool)
+    quickCheck (functorCompose' :: Two Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Three Int Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Three Int Int Int -> Bool)
+    quickCheck (functorCompose' :: Three Int Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Three' Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Three' Int Int -> Bool)
+    quickCheck (functorCompose' :: Three' Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Four Int Int Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Four Int Int Int Int -> Bool)
+    quickCheck (functorCompose' :: Four Int Int Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Four' Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Four' Int Int -> Bool)
+    quickCheck (functorCompose' :: Four' Int Int -> Fun Int Int -> Fun Int Int -> Bool)
-- 
cgit v1.2.3