From 152b564ef7afd40b1c82c10497e46591594c2367 Mon Sep 17 00:00:00 2001
From: NguyenNguyen <nguyenbk92@gmail.com>
Date: Thu, 4 Apr 2019 14:20:11 +0700
Subject: [PATCH] Refactoring and adding unit test of compareSignersLists

---
 consensus/posv/posv.go      | 21 +++++++++++++--------
 consensus/posv/posv_test.go | 26 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/consensus/posv/posv.go b/consensus/posv/posv.go
index 35177163ac..24cb26d059 100644
--- a/consensus/posv/posv.go
+++ b/consensus/posv/posv.go
@@ -428,14 +428,7 @@ func (c *Posv) verifyCascadingFields(chain consensus.ChainReader, header *types.
 		}
 		extraSuffix := len(header.Extra) - extraSeal
 		masternodesFromCheckpointHeader := common.ExtractAddressFromBytes(header.Extra[extraVanity:extraSuffix])
-		validSigners := true
-		sort.Slice(masternodesFromCheckpointHeader, func(i, j int) bool {
-			return masternodesFromCheckpointHeader[i].String() <= masternodesFromCheckpointHeader[j].String()
-		})
-		sort.Slice(signers, func(i, j int) bool {
-			return signers[i].String() <= signers[j].String()
-		})
-		validSigners = reflect.DeepEqual(masternodesFromCheckpointHeader, signers)
+		validSigners := compareSignersLists(masternodesFromCheckpointHeader, signers)
 		if !validSigners {
 			log.Error("Masternodes lists are different in checkpoint header and snapshot", "number", number, "masternodes_from_checkpoint_header", masternodesFromCheckpointHeader, "masternodes_in_snapshot", signers, "penList", penPenalties)
 			return errInvalidCheckpointSigners
@@ -451,6 +444,18 @@ func (c *Posv) verifyCascadingFields(chain consensus.ChainReader, header *types.
 	return c.verifySeal(chain, header, parents, fullVerify)
 }
 
+// compare 2 signers lists
+// return true if they are same elements, otherwise return false
+func compareSignersLists(list1 []common.Address, list2 []common.Address) bool {
+	sort.Slice(list1, func(i, j int) bool {
+		return list1[i].String() <= list1[j].String()
+	})
+	sort.Slice(list2, func(i, j int) bool {
+		return list2[i].String() <= list2[j].String()
+	})
+	return reflect.DeepEqual(list1, list2)
+}
+
 func (c *Posv) GetSnapshot(chain consensus.ChainReader, header *types.Header) (*Snapshot, error) {
 	number := header.Number.Uint64()
 	log.Trace("take snapshot", "number", number, "hash", header.Hash())
diff --git a/consensus/posv/posv_test.go b/consensus/posv/posv_test.go
index 1c0a5baeb1..1ccf9f7860 100644
--- a/consensus/posv/posv_test.go
+++ b/consensus/posv/posv_test.go
@@ -47,3 +47,29 @@ func TestGetM1M2FromCheckpointHeader(t *testing.T) {
 		}
 	}
 }
+
+func TestCompareSignersLists(t *testing.T) {
+	list1 := []common.Address{
+		common.StringToAddress("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		common.StringToAddress("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc"),
+		common.StringToAddress("dddddddddddddddddddddddddddddddddddddddd"),
+	}
+	list2 := []common.Address{
+		common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc"),
+		common.StringToAddress("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		common.StringToAddress("dddddddddddddddddddddddddddddddddddddddd"),
+		common.StringToAddress("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+	}
+	list3 := []common.Address{
+		common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc"),
+		common.StringToAddress("dddddddddddddddddddddddddddddddddddddddd"),
+		common.StringToAddress("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+	}
+	if !compareSignersLists(list1, list2) {
+		t.Error("list1 should be equal to list2", "list1", list1, "list2", list2)
+	}
+	if compareSignersLists(list1, list3) {
+		t.Error("list1 and list3 should not be same", "list1", list1, "list3", list3)
+	}
+}