Oneof.hs

{- | Round-trip + variant-overwrite tests for the oneof bridge
rewire. Exercises 'Proto.TH.loadProto'-generated codecs for
@Envelope@, whose @oneof envelope_choice@ produces an
@Envelope'EnvelopeChoice@ sum type via 'Proto.TH.mkOneofDataDecs'.
-}
module Test.Proto.Derive.Oneof (tests) where

import Data.ByteString qualified as BS
import Data.Text qualified as T
import Proto.Decode qualified as PD
import Proto.Encode qualified as PE
import Test.Proto.Derive.OneofInstances (
  Envelope (..),
  Envelope'EnvelopeChoice (..),
  Inner (..),
  defaultEnvelope,
  defaultInner,
 )
import Test.Syd


tests :: Spec
tests =
  describe
    "Proto.TH oneof bridge"
    $ sequence_
      [ it "no choice variant set: round-trips empty payload" $ do
          let e = defaultEnvelope
          let bs = PE.encodeMessage e
          bs `shouldBe` BS.empty
          PD.decodeMessage bs `shouldBe` Right e
      , it "label only: round-trips" $ do
          let e = defaultEnvelope {envelopeEnvelopeLabel = T.pack "labelled"}
          PD.decodeMessage (PE.encodeMessage e) `shouldBe` Right e
      , it "choice_url variant round-trips" $ do
          let e =
                defaultEnvelope
                  { envelopeEnvelopeLabel = T.pack "withUrl"
                  , envelopeEnvelopeChoice =
                      Just
                        ( Envelope'EnvelopeChoice'ChoiceUrl
                            (T.pack "https://example.test/x")
                        )
                  }
          PD.decodeMessage (PE.encodeMessage e) `shouldBe` Right e
      , it "choice_blob variant round-trips" $ do
          let e =
                defaultEnvelope
                  { envelopeEnvelopeChoice =
                      Just
                        ( Envelope'EnvelopeChoice'ChoiceBlob
                            (BS.pack [0xCA, 0xFE, 0xBA, 0xBE])
                        )
                  }
          PD.decodeMessage (PE.encodeMessage e) `shouldBe` Right e
      , it "choice_seed variant round-trips" $ do
          let e =
                defaultEnvelope
                  { envelopeEnvelopeChoice = Just (Envelope'EnvelopeChoice'ChoiceSeed 12345)
                  }
          PD.decodeMessage (PE.encodeMessage e) `shouldBe` Right e
      , it "choice_inner submessage variant round-trips" $ do
          let inner = defaultInner {innerInnerId = 99}
              e =
                defaultEnvelope
                  { envelopeEnvelopeLabel = T.pack "nested"
                  , envelopeEnvelopeChoice = Just (Envelope'EnvelopeChoice'ChoiceInner inner)
                  }
          PD.decodeMessage (PE.encodeMessage e) `shouldBe` Right e
      , it "later variant on the wire wins (proto3 oneof semantics)" $ do
          -- Concatenate two encodings that each set a different
          -- variant; per proto3 the last one wins on decode.
          let eUrl =
                defaultEnvelope
                  { envelopeEnvelopeChoice =
                      Just
                        ( Envelope'EnvelopeChoice'ChoiceUrl
                            (T.pack "old")
                        )
                  }
              eSeed =
                defaultEnvelope
                  { envelopeEnvelopeChoice = Just (Envelope'EnvelopeChoice'ChoiceSeed 7)
                  }
              combined = PE.encodeMessage eUrl `BS.append` PE.encodeMessage eSeed
          PD.decodeMessage combined `shouldBe` Right eSeed
      ]