tests: Add tests for decoding actual pack file

test/unit/Cardano/Wallet/PackfileSpec.hs

@@ -4,10 +4,13 @@ module Cardano.Wallet.PackfileSpec (spec) where
 
 import Prelude
 
+import qualified Data.ByteString.Char8 as B8
 import qualified Data.ByteString.Lazy.Char8 as L8
 
+import Data.Either
+    ( fromRight, isRight )
 import Test.Hspec
-    ( Spec, describe, it, shouldBe )
+    ( Spec, describe, it, shouldBe, shouldSatisfy )
 
 import Cardano.Wallet.Binary.Packfile
 
@@ -23,6 +26,11 @@ testTwoBlobs = packFileHeader
         <> "\0\0\0\11first block\0"
         <> "\0\0\0\12second block"
 
+-- Get this file from cardano-http-bridge with:
+-- wget -O test/data/epoch-mainnet-104 http://localhost:8080/mainnet/epoch/104
+testPackfile :: FilePath
+testPackfile = "test/data/epoch-mainnet-104"
+
 spec :: Spec
 spec = do
     describe "Decoding pack file" $ do
@@ -56,3 +64,16 @@ spec = do
         it "should reject extra data" $ do
             let decoded = decodePackfile (packFileHeader <> "a")
             decoded `shouldBe` Left (BlobDecodeError "not enough bytes")
+
+    describe "Decoding a mainnet pack file" $ do
+        it "should decode pack file for mainnet epoch 104" $ do
+            bs <- L8.readFile testPackfile
+            let decoded = decodePackfile bs
+            decoded `shouldSatisfy` isRight
+            length (fromRight [] decoded) `shouldBe` 21600
+
+        it "first blocks in pack file for mainnet epoch 104 should be valid" $ do
+            bs <- L8.readFile testPackfile
+            let Right (first:second:_) = decodePackfile bs
+            B8.length first `shouldBe` 648092
+            B8.length second `shouldBe` 1181