1 files changed, 238 insertions, 0 deletions
diff --git a/core/state/sync_test.go b/core/state/sync_test.go
new file mode 100644
index 000000000..f6afe8bd8
--- /dev/null
+++ b/core/state/sync_test.go
@@ -0,0 +1,238 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"bytes"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// testAccount is the data associated with an account used by the state tests.
+type testAccount struct {
+	address common.Address
+	balance *big.Int
+	nonce   uint64
+	code    []byte
+}
+
+// makeTestState create a sample test state to test node-wise reconstruction.
+func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
+	// Create an empty state
+	db, _ := ethdb.NewMemDatabase()
+	state := New(common.Hash{}, db)
+
+	// Fill it with some arbitrary data
+	accounts := []*testAccount{}
+	for i := byte(0); i < 255; i++ {
+		obj := state.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
+		acc := &testAccount{address: common.BytesToAddress([]byte{i})}
+
+		obj.AddBalance(big.NewInt(int64(11 * i)))
+		acc.balance = big.NewInt(int64(11 * i))
+
+		obj.SetNonce(uint64(42 * i))
+		acc.nonce = uint64(42 * i)
+
+		if i%3 == 0 {
+			obj.SetCode([]byte{i, i, i, i, i})
+			acc.code = []byte{i, i, i, i, i}
+		}
+		state.UpdateStateObject(obj)
+		accounts = append(accounts, acc)
+	}
+	root, _ := state.Commit()
+
+	// Return the generated state
+	return db, root, accounts
+}
+
+// checkStateAccounts cross references a reconstructed state with an expected
+// account array.
+func checkStateAccounts(t *testing.T, db ethdb.Database, root common.Hash, accounts []*testAccount) {
+	state := New(root, db)
+	for i, acc := range accounts {
+
+		if balance := state.GetBalance(acc.address); balance.Cmp(acc.balance) != 0 {
+			t.Errorf("account %d: balance mismatch: have %v, want %v", i, balance, acc.balance)
+		}
+		if nonce := state.GetNonce(acc.address); nonce != acc.nonce {
+			t.Errorf("account %d: nonce mismatch: have %v, want %v", i, nonce, acc.nonce)
+		}
+		if code := state.GetCode(acc.address); bytes.Compare(code, acc.code) != 0 {
+			t.Errorf("account %d: code mismatch: have %x, want %x", i, code, acc.code)
+		}
+	}
+}
+
+// Tests that an empty state is not scheduled for syncing.
+func TestEmptyStateSync(t *testing.T) {
+	empty := common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
+	db, _ := ethdb.NewMemDatabase()
+	if req := NewStateSync(empty, db).Missing(1); len(req) != 0 {
+		t.Errorf("content requested for empty state: %v", req)
+	}
+}
+
+// Tests that given a root hash, a state can sync iteratively on a single thread,
+// requesting retrieval tasks and returning all of them in one go.
+func TestIterativeStateSyncIndividual(t *testing.T) { testIterativeStateSync(t, 1) }
+func TestIterativeStateSyncBatched(t *testing.T)    { testIterativeStateSync(t, 100) }
+
+func testIterativeStateSync(t *testing.T, batch int) {
+	// Create a random state to copy
+	srcDb, srcRoot, srcAccounts := makeTestState()
+
+	// Create a destination state and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewStateSync(srcRoot, dstDb)
+
+	queue := append([]common.Hash{}, sched.Missing(batch)...)
+	for len(queue) > 0 {
+		results := make([]trie.SyncResult, len(queue))
+		for i, hash := range queue {
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results[i] = trie.SyncResult{hash, data}
+		}
+		if err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process results: %v", err)
+		}
+		queue = append(queue[:0], sched.Missing(batch)...)
+	}
+	// Cross check that the two states are in sync
+	checkStateAccounts(t, dstDb, srcRoot, srcAccounts)
+}
+
+// Tests that the trie scheduler can correctly reconstruct the state even if only
+// partial results are returned, and the others sent only later.
+func TestIterativeDelayedStateSync(t *testing.T) {
+	// Create a random state to copy
+	srcDb, srcRoot, srcAccounts := makeTestState()
+
+	// Create a destination state and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewStateSync(srcRoot, dstDb)
+
+	queue := append([]common.Hash{}, sched.Missing(0)...)
+	for len(queue) > 0 {
+		// Sync only half of the scheduled nodes
+		results := make([]trie.SyncResult, len(queue)/2+1)
+		for i, hash := range queue[:len(results)] {
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results[i] = trie.SyncResult{hash, data}
+		}
+		if err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process results: %v", err)
+		}
+		queue = append(queue[len(results):], sched.Missing(0)...)
+	}
+	// Cross check that the two states are in sync
+	checkStateAccounts(t, dstDb, srcRoot, srcAccounts)
+}
+
+// Tests that given a root hash, a trie can sync iteratively on a single thread,
+// requesting retrieval tasks and returning all of them in one go, however in a
+// random order.
+func TestIterativeRandomStateSyncIndividual(t *testing.T) { testIterativeRandomStateSync(t, 1) }
+func TestIterativeRandomStateSyncBatched(t *testing.T)    { testIterativeRandomStateSync(t, 100) }
+
+func testIterativeRandomStateSync(t *testing.T, batch int) {
+	// Create a random state to copy
+	srcDb, srcRoot, srcAccounts := makeTestState()
+
+	// Create a destination state and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewStateSync(srcRoot, dstDb)
+
+	queue := make(map[common.Hash]struct{})
+	for _, hash := range sched.Missing(batch) {
+		queue[hash] = struct{}{}
+	}
+	for len(queue) > 0 {
+		// Fetch all the queued nodes in a random order
+		results := make([]trie.SyncResult, 0, len(queue))
+		for hash, _ := range queue {
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results = append(results, trie.SyncResult{hash, data})
+		}
+		// Feed the retrieved results back and queue new tasks
+		if err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process results: %v", err)
+		}
+		queue = make(map[common.Hash]struct{})
+		for _, hash := range sched.Missing(batch) {
+			queue[hash] = struct{}{}
+		}
+	}
+	// Cross check that the two states are in sync
+	checkStateAccounts(t, dstDb, srcRoot, srcAccounts)
+}
+
+// Tests that the trie scheduler can correctly reconstruct the state even if only
+// partial results are returned (Even those randomly), others sent only later.
+func TestIterativeRandomDelayedStateSync(t *testing.T) {
+	// Create a random state to copy
+	srcDb, srcRoot, srcAccounts := makeTestState()
+
+	// Create a destination state and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewStateSync(srcRoot, dstDb)
+
+	queue := make(map[common.Hash]struct{})
+	for _, hash := range sched.Missing(0) {
+		queue[hash] = struct{}{}
+	}
+	for len(queue) > 0 {
+		// Sync only half of the scheduled nodes, even those in random order
+		results := make([]trie.SyncResult, 0, len(queue)/2+1)
+		for hash, _ := range queue {
+			delete(queue, hash)
+
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results = append(results, trie.SyncResult{hash, data})
+
+			if len(results) >= cap(results) {
+				break
+			}
+		}
+		// Feed the retrieved results back and queue new tasks
+		if err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process results: %v", err)
+		}
+		for _, hash := range sched.Missing(0) {
+			queue[hash] = struct{}{}
+		}
+	}
+	// Cross check that the two states are in sync
+	checkStateAccounts(t, dstDb, srcRoot, srcAccounts)
+}