server: refine TestProcessIgnoreMismatchMessage

Signed-off-by: Neil Shen <overvenus@gmail.com>

server/etcdserver/server_test.go

@@ -470,7 +470,7 @@ func TestApplyConfigChangeUpdatesConsistIndex(t *testing.T) {
 		lgMu:         new(sync.RWMutex),
 		lg:           lg,
 		memberId:     1,
-		r:            *realisticRaftNode(lg, nil),
+		r:            *realisticRaftNode(lg, 1, nil),
 		cluster:      cl,
 		w:            wait.New(),
 		consistIndex: ci,
@@ -514,7 +514,7 @@ func TestApplyConfigChangeUpdatesConsistIndex(t *testing.T) {
 	assert.Equal(t, consistIndex, rindex)
 }
 
-func realisticRaftNode(lg *zap.Logger, snap *raftpb.Snapshot) *raftNode {
+func realisticRaftNode(lg *zap.Logger, id uint64, snap *raftpb.Snapshot) *raftNode {
 	storage := raft.NewMemoryStorage()
 	storage.SetHardState(raftpb.HardState{Commit: 0, Term: 0})
 	if snap != nil {
@@ -524,7 +524,7 @@ func realisticRaftNode(lg *zap.Logger, snap *raftpb.Snapshot) *raftNode {
 		}
 	}
 	c := &raft.Config{
-		ID:              1,
+		ID:              id,
 		ElectionTick:    10,
 		HeartbeatTick:   1,
 		Storage:         storage,
@@ -906,20 +906,25 @@ func TestProcessIgnoreMismatchMessage(t *testing.T) {
 	defer betesting.Close(t, be)
 	cl.SetBackend(schema.NewMembershipBackend(lg, be))
 
-	// Bootstrap a 3-node cluster
+	// Bootstrap a 3-node cluster, member IDs: 1 2 3.
 	cl.AddMember(&membership.Member{ID: types.ID(1)}, true)
 	cl.AddMember(&membership.Member{ID: types.ID(2)}, true)
 	cl.AddMember(&membership.Member{ID: types.ID(3)}, true)
-	r := realisticRaftNode(lg, &raftpb.Snapshot{
+	// r is initialized with ID 1.
+	r := realisticRaftNode(lg, 1, &raftpb.Snapshot{
 		Metadata: raftpb.SnapshotMetadata{
-			Index:     11, // magic number
-			Term:      11, // magic number
-			ConfState: raftpb.ConfState{Voters: []uint64{1, 2, 3}},
+			Index: 11, // Magic number.
+			Term:  11, // Magic number.
+			ConfState: raftpb.ConfState{
+				// Member ID list.
+				Voters: []uint64{1, 2, 3},
+			},
 		},
 	})
 	s := &EtcdServer{
 		lgMu:         new(sync.RWMutex),
 		lg:           lg,
+		memberId:     1,
 		r:            *r,
 		v2store:      st,
 		cluster:      cl,
@@ -931,13 +936,13 @@ func TestProcessIgnoreMismatchMessage(t *testing.T) {
 	// Mock a mad switch dispatching messages to wrong node.
 	m := raftpb.Message{
 		Type:   raftpb.MsgHeartbeat,
-		To:     2, // Wrong ID.
+		To:     2, // Wrong ID, s.MemberId() is 1.
 		From:   3,
 		Term:   11,
-		Commit: 42, // Commit is larger than the last index.
+		Commit: 42, // Commit is larger than the last index 11.
 	}
 	if types.ID(m.To) == s.MemberId() {
-		t.Fatalf("To must mismatch")
+		t.Fatalf("m.To (%d) is expected to mismatch s.MemberId (%d)", m.To, s.MemberId())
 	}
 	err := s.Process(context.Background(), m)
 	if err == nil {