Put test helpers into Test.Hspec.GraphQL

src/Test/Hspec/GraphQL.hs

@@ -0,0 +1,48 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
+{-# LANGUAGE ExplicitForAll #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+
+-- | Test helpers.
+module Test.Hspec.GraphQL
+    ( shouldResolve
+    , shouldResolveTo
+    ) where
+
+import Control.Monad.Catch (MonadCatch)
+import qualified Data.Sequence as Seq
+import Data.Text (Text)
+import Language.GraphQL.Error
+import Language.GraphQL.Execute
+import Test.Hspec.Expectations
+    ( Expectation
+    , expectationFailure
+    , shouldBe
+    , shouldSatisfy
+    )
+
+-- | Asserts that a query resolves to some value.
+shouldResolveTo :: (MonadCatch m, Serialize b, Eq b, Show b)
+    => Either (ResponseEventStream m b) (Response b)
+    -> b
+    -> Expectation
+shouldResolveTo (Right Response{ errors = Seq.Empty, data' }) expected =
+    data' `shouldBe` expected
+shouldResolveTo _ _ = expectationFailure
+    "the query is expected to resolve to a value, but it resolved to an event stream"
+
+-- | Asserts that the response doesn't contain any errors.
+shouldResolve :: (MonadCatch m, Serialize b)
+    => (Text -> IO (Either (ResponseEventStream m b) (Response b)))
+    -> Text
+    -> Expectation
+shouldResolve executor query = do
+    actual <- executor query
+    case actual of
+        Right Response{ errors } -> errors `shouldSatisfy` Seq.null
+        _ -> expectationFailure
+            "the query is expected to resolve to a value, but it resolved to an event stream"