Tests.QuickCheckUtils: i Arbitrary (NotEmpty {,L}Text): refact

tests/Tests/QuickCheckUtils.hs

@@ -110,16 +110,24 @@ instance Arbitrary BigInt where
 newtype NotEmpty a = NotEmpty { notEmpty :: a }
  deriving (Eq, Ord, Show)
 
+toNotEmptyBy :: Functor m => ([Char] -> a) -> m (NonEmptyList Char) -> m (NotEmpty a)
+toNotEmptyBy f = fmap (coerce f)
+
+arbitraryNotEmptyBy :: ([Char] -> a) -> Gen (NotEmpty a)
+arbitraryNotEmptyBy f = toNotEmptyBy f arbitrary
+
+shrinkNotEmptyBy :: ([Char] -> a) -> (a -> [Char]) -> NotEmpty a -> [NotEmpty a]
+shrinkNotEmptyBy g f =
+  toNotEmptyBy g . shrink . coerce f
 
 instance Arbitrary (NotEmpty T.Text) where
-    arbitrary   = fmap (NotEmpty . T.pack . getNonEmpty) arbitrary
-    shrink      = fmap (NotEmpty . T.pack . getNonEmpty)
-                . shrink . NonEmpty . T.unpack . notEmpty
+    arbitrary   = arbitraryNotEmptyBy T.pack
+    shrink      = shrinkNotEmptyBy T.pack T.unpack
 
 instance Arbitrary (NotEmpty TL.Text) where
-    arbitrary   = fmap (NotEmpty . TL.pack . getNonEmpty) arbitrary
-    shrink      = fmap (NotEmpty . TL.pack . getNonEmpty)
-                . shrink . NonEmpty . TL.unpack . notEmpty
+    arbitrary   = arbitraryNotEmptyBy TL.pack
+    shrink      = shrinkNotEmptyBy TL.pack TL.unpack
+
 
 data DecodeErr = Lenient | Ignore | Strict | Replace
  deriving (Show, Eq, Bounded, Enum)