Add basic output object type support

tests/Test/RootOperationSpec.hs

@@ -0,0 +1,62 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE QuasiQuotes #-}
+module Test.RootOperationSpec
+    ( spec
+    ) where
+
+import Data.Aeson ((.=), object)
+import Data.List.NonEmpty (NonEmpty(..))
+import Language.GraphQL
+import qualified Language.GraphQL.Schema as Schema
+import Test.Hspec (Spec, describe, it, shouldBe)
+import Text.RawString.QQ (r)
+import Language.GraphQL.Type.Definition
+import Language.GraphQL.Type.Schema
+
+schema :: Schema IO
+schema = Schema
+    (ObjectType "Query" queryResolvers)
+    (Just $ ObjectType "Mutation" mutationResolvers)
+  where
+    queryResolvers = Schema.resolversToMap $ garment :| []
+    mutationResolvers = Schema.resolversToMap $ increment :| []
+    garment = Schema.object "garment" $ pure
+        [ Schema.scalar "circumference" $ pure (60 :: Int)
+        ]
+    increment = Schema.scalar "incrementCircumference"
+        $ pure (61 :: Int)
+
+spec :: Spec
+spec =
+    describe "Root operation type" $ do
+        it "returns objects from the root resolvers" $ do
+            let querySource = [r|
+              {
+                garment {
+                  circumference
+                }
+              }
+            |]
+                expected = object
+                    [ "data" .= object
+                        [ "garment" .= object
+                            [ "circumference" .= (60 :: Int)
+                            ]
+                        ]
+                    ]
+            actual <- graphql schema querySource
+            actual `shouldBe` expected
+
+        it "chooses Mutation" $ do
+            let querySource = [r|
+              mutation {
+                incrementCircumference
+              }
+            |]
+                expected = object
+                    [ "data" .= object
+                        [ "incrementCircumference" .= (61 :: Int)
+                        ]
+                    ]
+            actual <- graphql schema querySource
+            actual `shouldBe` expected