tests: Add tests for pack file decoding

cardano-wallet.cabal

@@ -107,4 +107,5 @@ test-suite unit
   other-modules:
       Cardano.Wallet.BinaryHelpers
     , Cardano.Wallet.BinarySpec
+    , Cardano.Wallet.PackfileSpec
     , Cardano.Wallet.PrimitiveSpec

test/unit/Cardano/Wallet/PackfileSpec.hs

@@ -0,0 +1,72 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Cardano.Wallet.PackfileSpec (spec) where
+
+import Prelude
+
+import qualified Data.ByteString.Lazy.Char8 as L8
+import qualified Data.ByteString.Char8 as S8
+
+import Test.Hspec
+    ( Spec, describe, it, shouldBe, shouldSatisfy )
+import Data.Either
+
+import Cardano.Wallet.Binary.Packfile
+
+-- version 1 header
+packFileHeader :: L8.ByteString
+packFileHeader = "\254CARDANOPACK\NUL\NUL\NUL\SOH"
+
+test1 :: L8.ByteString
+test1 = packFileHeader <> "\0\0\0\5hello\0\0\0"
+
+test2 :: L8.ByteString
+test2 = packFileHeader
+        <> "\0\0\0\11first block\0"
+        <> "\0\0\0\12second block"
+
+spec :: Spec
+spec = do
+    describe "Decoding pack file" $ do
+        it "should decode a packfile" $ do
+            -- Get this file with
+            -- wget -O test/data/epoch-mainnet-104 http://localhost:8080/mainnet/epoch/104
+            bs <- L8.readFile "test/data/epoch-mainnet-104"
+            let decoded = decodePackfile bs
+            decoded `shouldSatisfy` isRight
+            length (fromRight [] decoded) `shouldBe` 21600
+
+        it "first blocks in pack file should be valid" $ do
+            bs <- L8.readFile "test/data/epoch-mainnet-104"
+            let Right (first:second:_) = decodePackfile bs
+            S8.length first `shouldBe` 648092
+            S8.length second `shouldBe` 1181
+
+        it "should not decode junk" $ do
+            let decoded = decodePackfile "junkjunkjunkjunk"
+            decoded `shouldBe` Left MissingMagicError
+
+        it "should ensure pack file type" $ do
+            let decoded = decodePackfile "\254CARDANOYOLO\NUL\NUL\NUL\SOH"
+            decoded `shouldBe` Left WrongFileTypeError
+
+        it "should ensure pack file version" $ do
+            let decoded = decodePackfile "\254CARDANOPACK\NUL\NUL\NUL\2"
+            decoded `shouldBe` Left VersionTooNewError
+
+        it "should decode an empty pack file" $ do
+            decodePackfile packFileHeader `shouldBe` Right []
+
+        it "should decode a single blob" $ do
+            decodePackfile test1 `shouldBe` Right ["hello"]
+
+        it "should decode multiple blobs" $ do
+            decodePackfile test2 `shouldBe` Right ["first block", "second block"]
+
+        it "should not decode overly large blobs" $ do
+            let decoded = decodePackfile (packFileHeader <> "\64\0\0\0")
+            decoded `shouldBe` Left (BlobDecodeError "read block of size: 1073741824")
+
+        it "should reject extra data" $ do
+            let decoded = decodePackfile (packFileHeader <> "a")
+            decoded `shouldBe` Left (BlobDecodeError "not enough bytes")