Upd: add tests, but they work

ghc-802.yaml

@@ -5,3 +5,4 @@ packages:
 
 extra-deps:
 - dom-parser-3.0.0
+- generic-arbitrary-0.1.0

ghc-821.yaml

@@ -5,3 +5,4 @@ packages:
 
 extra-deps:
 - dom-parser-3.0.0
+- generic-arbitrary-0.1.0

stack.yaml

@@ -5,3 +5,4 @@ packages:
 
 extra-deps:
 - dom-parser-3.0.0
+- generic-arbitrary-0.1.0

test/Main.hs

@@ -1,7 +1,31 @@
 {-# OPTIONS -fno-warn-unused-imports #-}
 module Main where
 
+import Control.Exception
+import Text.XML
+import Data.Default
+import System.IO.Unsafe
+import Test.Hspec
+import Test.Hspec.QuickCheck
+import Test.QuickCheck
 import TestDefs
+import Text.XML.DOM.Parser
+import Text.XML.Writer
+
+isomorphicFoo :: XmlRoot -> Property
+isomorphicFoo a = a === isogen
+  where
+    isogen :: XmlRoot
+    isogen =
+      let
+        doc = document "Root" $ toXML a
+        res = case runDomParser doc fromDom of
+          Left e -> unsafePerformIO $ do
+            pprint doc
+            throwIO e
+          Right a' -> a'
+      in res
 
 main :: IO ()
-main = return ()
+main = hspec $ do
+  prop "isomorphic" isomorphicFoo

test/TestDefs.hs

@@ -1,12 +1,14 @@
 {-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 {-# OPTIONS -ddump-splices #-}
 
 module TestDefs where
 
+import Data.List.NonEmpty
 import Data.THGen.XML
+import GHC.Generics (Generic)
+import Test.QuickCheck.Arbitrary.Generic
+import Test.QuickCheck.Instances ()
 
 "Bar" =:= enum
   & "baroque"
@@ -25,3 +27,23 @@ import Data.THGen.XML
   + "Bar"
   ? "Baz" [t|Text|]
   !% "Quux"
+  ?% "Muux" [t|XmlQuux|]
+
+"Root" =:= record
+  ! "Foo"
+
+deriving instance Generic XmlRoot
+
+instance Arbitrary XmlRoot where
+  arbitrary = genericArbitrary
+  shrink = genericShrink
+
+deriving instance Generic XmlFoo
+
+instance Arbitrary XmlFoo where
+  arbitrary = genericArbitrary
+  shrink = genericShrink
+
+instance Arbitrary (NonEmpty XmlBar) where
+  arbitrary = genericArbitrary
+  shrink = genericShrink

xml-isogen.cabal

@@ -45,17 +45,35 @@ library
   hs-source-dirs:      src
 
   default-language:    Haskell2010
-  default-extensions:  TemplateHaskell
-                       LambdaCase
-                       FlexibleInstances
-                       TypeFamilies
-                       TupleSections
+  default-extensions:  FlexibleInstances
+                     , LambdaCase
+                     , TemplateHaskell
+                     , TupleSections
+                     , TypeFamilies
 
 test-suite spec
   type:               exitcode-stdio-1.0
   hs-source-dirs:     test
   main-is:            Main.hs
   other-modules:      TestDefs
-  build-depends:      base, xml-isogen
+  build-depends:      base
+                    , QuickCheck
+                    , data-default
+                    , dom-parser
+                    , generic-arbitrary
+                    , hspec
+                    , quickcheck-instances
+                    , semigroups
+                    , xml-conduit
+                    , xml-conduit-writer
+                    , xml-isogen
   default-language:   Haskell2010
+  default-extensions:  DeriveGeneric
+                     , FlexibleInstances
+                     , LambdaCase
+                     , OverloadedStrings
+                     , StandaloneDeriving
+                     , TemplateHaskell
+                     , TupleSections
+                     , TypeFamilies
   ghc-options:        -Wall -fno-warn-missing-signatures