Provide custom Show instances for AST values

tests/Language/GraphQL/AST/DocumentSpec.hs

@@ -0,0 +1,20 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE OverloadedStrings #-}
+module Language.GraphQL.AST.DocumentSpec
+    ( spec
+    ) where
+
+import Language.GraphQL.AST.Document
+import Test.Hspec (Spec, describe, it, shouldBe)
+
+spec :: Spec
+spec = do
+    describe "Document" $ do
+        it "shows objects" $
+            let zero = Location 0 0
+                object = ConstObject
+                    [ ObjectField "field1" (Node (ConstFloat 1.2) zero) zero
+                    , ObjectField "field2" (Node ConstNull zero) zero
+                    ]
+                expected = "{ field1: 1.2, field2: null }"
+             in show object `shouldBe` expected

tests/Language/GraphQL/ValidateSpec.hs

@@ -851,7 +851,7 @@ spec =
             |]
                 expected = Error
                     { message =
-                        "Value ConstInt 3 cannot be coerced to type \"Boolean\"."
+                        "Value 3 cannot be coerced to type \"Boolean\"."
                     , locations = [AST.Location 4 48]
                     }
              in validate queryString `shouldBe` [expected]