From 5442a196c3ad85b512597afd1ae785f44b3e7453 Mon Sep 17 00:00:00 2001
From: ptrus <ptrusr@gmail.com>
Date: Fri, 9 Oct 2020 18:47:29 +0200
Subject: [PATCH] roothash: Add consistent hash test for ComputeResultsHeader

---
 go/roothash/api/commitment/executor.go      |  8 ++---
 go/roothash/api/commitment/executor_test.go | 35 +++++++++++++++++++
 runtime/src/common/roothash.rs              | 37 ++++++++++++++++++---
 runtime/src/dispatcher.rs                   |  6 ++--
 4 files changed, 75 insertions(+), 11 deletions(-)
 create mode 100644 go/roothash/api/commitment/executor_test.go

diff --git a/go/roothash/api/commitment/executor.go b/go/roothash/api/commitment/executor.go
index 4f68a854100..8e8c3af3a1b 100644
--- a/go/roothash/api/commitment/executor.go
+++ b/go/roothash/api/commitment/executor.go
@@ -36,10 +36,10 @@ type ComputeResultsHeader struct {
 	PreviousHash hash.Hash `json:"previous_hash"`
 
 	// Optional fields (may be absent for failure indication).
-
-	IORoot    *hash.Hash       `json:"io_root,omitempty"`
-	StateRoot *hash.Hash       `json:"state_root,omitempty"`
-	Messages  []*block.Message `json:"messages,omitempty"`
+	// TODO: add omitempty but make it work with rust side.
+	IORoot    *hash.Hash       `json:"io_root"`
+	StateRoot *hash.Hash       `json:"state_root"`
+	Messages  []*block.Message `json:"messages"`
 }
 
 // IsParentOf returns true iff the header is the parent of a child header.
diff --git a/go/roothash/api/commitment/executor_test.go b/go/roothash/api/commitment/executor_test.go
new file mode 100644
index 00000000000..fea10f60f25
--- /dev/null
+++ b/go/roothash/api/commitment/executor_test.go
@@ -0,0 +1,35 @@
+package commitment
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/oasisprotocol/oasis-core/go/common/crypto/hash"
+)
+
+func TestConsistentHash(t *testing.T) {
+	// NOTE: These hashes MUST be synced with runtime/src/common/roothash.rs.
+	var emptyHeaderHash hash.Hash
+	_ = emptyHeaderHash.UnmarshalHex("56b0efb0de294bd5968bfa18fd71523455430f673c941ed38598e3329178fd78")
+
+	var empty ComputeResultsHeader
+	require.EqualValues(t, emptyHeaderHash, empty.EncodedHash())
+
+	var emptyRoot hash.Hash
+	emptyRoot.Empty()
+
+	var populatedHeaderHash hash.Hash
+	_ = populatedHeaderHash.UnmarshalHex("9cfe012756033317199081cbc2741b4f783386b0818eba9573e20ef4df33c604")
+
+	populated := ComputeResultsHeader{
+		Round:        42,
+		PreviousHash: emptyHeaderHash,
+		IORoot:       &emptyRoot,
+		StateRoot:    &emptyRoot,
+		Messages:     nil,
+	}
+	fmt.Println(populated.EncodedHash().String())
+	require.EqualValues(t, populatedHeaderHash, populated.EncodedHash())
+}
diff --git a/runtime/src/common/roothash.rs b/runtime/src/common/roothash.rs
index 86a76d6e954..07c2ce1014e 100644
--- a/runtime/src/common/roothash.rs
+++ b/runtime/src/common/roothash.rs
@@ -102,11 +102,18 @@ pub struct ComputeResultsHeader {
     /// Hash of the previous block header this batch was computed against.
     pub previous_hash: Hash,
     /// The I/O merkle root.
-    pub io_root: Hash,
+    pub io_root: Option<Hash>,
     /// The root hash of the state after computing this batch.
-    pub state_root: Hash,
+    pub state_root: Option<Hash>,
     /// Messages sent from this batch.
-    pub messages: Vec<Message>,
+    pub messages: Option<Vec<Message>>,
+}
+
+impl ComputeResultsHeader {
+    /// Returns a hash of an encoded header.
+    pub fn encoded_hash(&self) -> Hash {
+        Hash::digest_bytes(&cbor::to_vec(&self))
+    }
 }
 
 #[cfg(test)]
@@ -114,7 +121,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_consistent_hash() {
+    fn test_consistent_hash_header() {
         // NOTE: These hashes MUST be synced with go/roothash/api/block/header_test.go.
         let empty = Header::default();
         assert_eq!(
@@ -139,4 +146,26 @@ mod tests {
             Hash::from("c39e8aefea5a1f794fb57f294a4ea8599381cd8739e67a8a9acb7763b54a630a")
         );
     }
+
+    #[test]
+    fn test_consistent_hash_compute_results_header() {
+        // NOTE: These hashes MUST be synced with go/roothash/api/commitment/executor_test.go.
+        let empty = ComputeResultsHeader::default();
+        assert_eq!(
+            empty.encoded_hash(),
+            Hash::from("56b0efb0de294bd5968bfa18fd71523455430f673c941ed38598e3329178fd78")
+        );
+
+        let populated = ComputeResultsHeader {
+            round: 42,
+            previous_hash: empty.encoded_hash(),
+            io_root: Some(Hash::empty_hash()),
+            state_root: Some(Hash::empty_hash()),
+            messages: None,
+        };
+        assert_eq!(
+            populated.encoded_hash(),
+            Hash::from("9cfe012756033317199081cbc2741b4f783386b0818eba9573e20ef4df33c604")
+        );
+    }
 }
diff --git a/runtime/src/dispatcher.rs b/runtime/src/dispatcher.rs
index 15405d5157e..879dfca5637 100644
--- a/runtime/src/dispatcher.rs
+++ b/runtime/src/dispatcher.rs
@@ -406,9 +406,9 @@ impl Dispatcher {
                     let header = ComputeResultsHeader {
                         round: block.header.round + 1,
                         previous_hash: block.header.encoded_hash(),
-                        io_root,
-                        state_root: new_state_root,
-                        messages,
+                        io_root: Some(io_root),
+                        state_root: Some(new_state_root),
+                        messages: Some(messages),
                     };
 
                     debug!(self.logger, "Transaction batch execution complete";