From 08d802b78fdb531717d7de642d4a38d068d7c183 Mon Sep 17 00:00:00 2001
From: Daniel Firth <daniel.firth@iohk.io>
Date: Fri, 2 May 2025 19:24:57 +0000
Subject: [PATCH] Add genBlockHeader functions to Test.Gen.Cardano.Api.Typed

---
 cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs b/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
index 90c41048ba..400e19285d 100644
--- a/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
+++ b/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
@@ -137,6 +137,10 @@ module Test.Gen.Cardano.Api.Typed
   , genMintWitnessable
   , genPlutusScriptWitness
   , genIndexedPlutusScriptWitness
+  , genBlockNo
+  , genBlockHeader
+  , genBlockHeaderAt
+  , genBlockHeaderHash
   )
 where
 
@@ -1488,3 +1492,31 @@ genScriptWitnessForMint sbe = do
         NoScriptDatumForMint
         scriptRedeemer
         <$> genExecutionUnits
+
+genBlockNo :: Gen BlockNo
+genBlockNo = BlockNo <$> Gen.word64 Range.constantBounded
+
+-- | Fully arbitrary block header with completely random hash.
+genBlockHeader :: Gen BlockHeader
+genBlockHeader = genSlotNo >>= genBlockHeaderAt
+
+-- | Generate a random block header with completely random hash, but at a
+-- certain slot.
+genBlockHeaderAt :: SlotNo -> Gen BlockHeader
+genBlockHeaderAt slotNo = BlockHeader slotNo <$> genBlockHeaderHash <*> genBlockNo
+
+-- | Generate a random block header hash.
+-- This will error if the hash size of block headers changes (currently 32 bytes).
+genBlockHeaderHash :: Gen (Hash BlockHeader)
+genBlockHeaderHash =
+  unsafeBlockHeaderHashFromBytes . BS.pack <$> Gen.list (Range.singleton 32) Q.arbitrary
+ where
+  unsafeBlockHeaderHashFromBytes bytes =
+    case deserialiseFromRawBytes (proxyToAsType Proxy) bytes of
+      Left e ->
+        error $
+          "unsafeBlockHeaderHashFromBytes: failed on bytes "
+            <> show bytes
+            <> " with error "
+            <> show e
+      Right h -> h