From f90fdbcc360753c5f0d0a0a777e6f05a97263fce Mon Sep 17 00:00:00 2001
From: Jasper Van der Jeugt <jaspervdj@gmail.com>
Date: Sat, 4 Dec 2010 15:39:03 +0100
Subject: [PATCH] Simple arbitrary instances

---
 .ghci                              |  1 +
 tests/Text/Digestive/Tests/Util.hs | 36 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 .ghci
 create mode 100644 tests/Text/Digestive/Tests/Util.hs

diff --git a/.ghci b/.ghci
new file mode 100644
index 0000000..3614a96
--- /dev/null
+++ b/.ghci
@@ -0,0 +1 @@
+:set -itests
diff --git a/tests/Text/Digestive/Tests/Util.hs b/tests/Text/Digestive/Tests/Util.hs
new file mode 100644
index 0000000..4378a41
--- /dev/null
+++ b/tests/Text/Digestive/Tests/Util.hs
@@ -0,0 +1,36 @@
+module Text.Digestive.Tests.Util
+    ( Id (..)
+    ) where
+
+import Control.Applicative (Applicative (..), (<$>))
+import Test.QuickCheck (Arbitrary (..))
+
+import Text.Digestive.Result
+import Text.Digestive.Types
+
+-- | An ID Monad
+--
+newtype Id a = Id {unId :: a}
+
+instance Functor Id where
+    fmap f (Id x) = Id $ f x
+
+instance Applicative Id where
+    pure = Id
+    (Id f) <*> (Id x) = Id $ f x
+
+instance Monad Id where
+    return = Id
+    (Id x) >>= f = f x
+
+instance Arbitrary a => Arbitrary (Result e a) where
+    arbitrary = Ok <$> arbitrary
+
+instance Arbitrary v => Arbitrary (View e v) where
+    arbitrary = View . const <$> arbitrary
+
+instance (Monad m, Arbitrary v, Arbitrary a) => Arbitrary (Form m i e v a) where
+    arbitrary = do
+        v <- arbitrary
+        r <- arbitrary
+        return $ Form $ return (v, r)