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diff --git a/tests/Language/GraphQL/AST/Arbitrary.hs b/tests/Language/GraphQL/AST/Arbitrary.hs
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+++ b/tests/Language/GraphQL/AST/Arbitrary.hs
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+{-# LANGUAGE OverloadedStrings #-}
+
+module Language.GraphQL.AST.Arbitrary where
+
+import qualified Language.GraphQL.AST.Document as Doc
+import Test.QuickCheck.Arbitrary (Arbitrary (arbitrary))
+import Test.QuickCheck (oneof, elements, listOf, resize, NonEmptyList (..))
+import Test.QuickCheck.Gen (Gen (..))
+import Data.Text (Text, pack)
+
+newtype AnyPrintableChar = AnyPrintableChar { getAnyPrintableChar :: Char } deriving (Eq, Show)
+
+alpha :: String
+alpha = ['a'..'z'] <> ['A'..'Z']
+
+num :: String
+num = ['0'..'9']
+
+instance Arbitrary AnyPrintableChar where
+    arbitrary = AnyPrintableChar <$> elements chars
+        where
+           chars = alpha <> num <> ['_'] 
+
+newtype AnyPrintableText = AnyPrintableText { getAnyPrintableText :: Text } deriving (Eq, Show)
+
+instance Arbitrary AnyPrintableText where
+    arbitrary = do
+        nonEmptyStr <- getNonEmpty <$> (arbitrary :: Gen (NonEmptyList AnyPrintableChar))
+        pure $ AnyPrintableText (pack $ map getAnyPrintableChar nonEmptyStr)
+
+-- https://spec.graphql.org/June2018/#Name
+newtype AnyName = AnyName { getAnyName :: Text } deriving (Eq, Show)
+
+instance Arbitrary AnyName where
+    arbitrary = do
+        firstChar <- elements $ alpha <> ['_']
+        rest <- (arbitrary :: Gen [AnyPrintableChar])
+        pure $ AnyName (pack $ firstChar : map getAnyPrintableChar rest)
+
+newtype AnyLocation = AnyLocation { getAnyLocation :: Doc.Location } deriving (Eq, Show)
+
+instance Arbitrary AnyLocation where
+    arbitrary = AnyLocation <$> (Doc.Location <$> arbitrary <*> arbitrary)
+
+newtype AnyNode a = AnyNode { getAnyNode :: Doc.Node a } deriving (Eq, Show)
+
+instance Arbitrary a => Arbitrary (AnyNode a) where
+    arbitrary = do
+        (AnyLocation location') <- arbitrary
+        node' <- flip Doc.Node location' <$> arbitrary
+        pure $ AnyNode node'
+
+newtype AnyObjectField a = AnyObjectField { getAnyObjectField :: Doc.ObjectField a } deriving (Eq, Show)
+
+instance Arbitrary a => Arbitrary (AnyObjectField a) where
+    arbitrary = do
+        name' <- getAnyName <$> arbitrary
+        value' <- getAnyNode <$> arbitrary
+        location' <- getAnyLocation <$> arbitrary
+        pure $ AnyObjectField $ Doc.ObjectField name' value' location'
+
+newtype AnyValue = AnyValue { getAnyValue :: Doc.Value } deriving (Eq, Show)
+
+instance Arbitrary AnyValue where
+    arbitrary = AnyValue <$> oneof
+        [ variableGen
+        , Doc.Int <$> arbitrary
+        , Doc.Float <$> arbitrary
+        , Doc.String <$> (getAnyPrintableText <$> arbitrary)
+        , Doc.Boolean <$> arbitrary
+        , MkGen $ \_ _ -> Doc.Null
+        , Doc.Enum <$> (getAnyName <$> arbitrary)
+        , Doc.List <$> listGen
+        , Doc.Object <$> objectGen
+        ]
+            where
+                variableGen :: Gen Doc.Value
+                variableGen = Doc.Variable <$> (getAnyName <$> arbitrary)
+                listGen :: Gen [Doc.Node Doc.Value]
+                listGen = (resize 5 . listOf) nodeGen
+                nodeGen = do
+                    node' <- getAnyNode <$> (arbitrary :: Gen (AnyNode AnyValue))
+                    pure (getAnyValue <$> node')
+                objectGen :: Gen [Doc.ObjectField Doc.Value]
+                objectGen = resize 1 $ do
+                    list <- getNonEmpty <$> (arbitrary :: Gen (NonEmptyList (AnyObjectField AnyValue)))
+                    pure $ map (fmap getAnyValue . getAnyObjectField) list
+
+newtype AnyArgument a = AnyArgument { getAnyArgument :: Doc.Argument } deriving (Eq, Show)
+
+instance Arbitrary a => Arbitrary (AnyArgument a) where
+    arbitrary = do
+        name' <- getAnyName <$> arbitrary
+        (AnyValue value') <- arbitrary
+        (AnyLocation location') <- arbitrary
+        pure $ AnyArgument $ Doc.Argument name' (Doc.Node value' location') location'
+
+printArgument :: AnyArgument AnyValue -> Text
+printArgument (AnyArgument (Doc.Argument name' (Doc.Node value' _) _)) = name' <> ": " <> (pack . show) value'