Add tests for FastSyncChainDownloader as a whole. (#758)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/sync/fastsync/FastSyncChainDownloaderTest.java

@@ -0,0 +1,171 @@
+/*
+ * Copyright 2019 ConsenSys AG.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package tech.pegasys.pantheon.ethereum.eth.sync.fastsync;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static tech.pegasys.pantheon.ethereum.p2p.wire.messages.DisconnectMessage.DisconnectReason.TOO_MANY_PEERS;
+
+import tech.pegasys.pantheon.ethereum.ProtocolContext;
+import tech.pegasys.pantheon.ethereum.chain.Blockchain;
+import tech.pegasys.pantheon.ethereum.chain.MutableBlockchain;
+import tech.pegasys.pantheon.ethereum.eth.manager.EthContext;
+import tech.pegasys.pantheon.ethereum.eth.manager.EthProtocolManager;
+import tech.pegasys.pantheon.ethereum.eth.manager.EthProtocolManagerTestUtil;
+import tech.pegasys.pantheon.ethereum.eth.manager.RespondingEthPeer;
+import tech.pegasys.pantheon.ethereum.eth.manager.RespondingEthPeer.Responder;
+import tech.pegasys.pantheon.ethereum.eth.manager.ethtaskutils.BlockchainSetupUtil;
+import tech.pegasys.pantheon.ethereum.eth.sync.SynchronizerConfiguration;
+import tech.pegasys.pantheon.ethereum.eth.sync.state.SyncState;
+import tech.pegasys.pantheon.ethereum.mainnet.ProtocolSchedule;
+import tech.pegasys.pantheon.metrics.LabelledMetric;
+import tech.pegasys.pantheon.metrics.OperationTimer;
+import tech.pegasys.pantheon.metrics.noop.NoOpMetricsSystem;
+
+import java.util.concurrent.CompletableFuture;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class FastSyncChainDownloaderTest {
+
+  protected ProtocolSchedule<Void> protocolSchedule;
+  protected EthProtocolManager ethProtocolManager;
+  protected EthContext ethContext;
+  protected ProtocolContext<Void> protocolContext;
+  private SyncState syncState;
+
+  protected MutableBlockchain localBlockchain;
+  private BlockchainSetupUtil<Void> otherBlockchainSetup;
+  protected Blockchain otherBlockchain;
+  private LabelledMetric<OperationTimer> ethTaskTimer;
+
+  @Before
+  public void setupTest() {
+    final BlockchainSetupUtil<Void> localBlockchainSetup = BlockchainSetupUtil.forTesting();
+    localBlockchain = localBlockchainSetup.getBlockchain();
+    otherBlockchainSetup = BlockchainSetupUtil.forTesting();
+    otherBlockchain = otherBlockchainSetup.getBlockchain();
+
+    protocolSchedule = localBlockchainSetup.getProtocolSchedule();
+    protocolContext = localBlockchainSetup.getProtocolContext();
+    ethProtocolManager =
+        EthProtocolManagerTestUtil.create(localBlockchain, localBlockchainSetup.getWorldArchive());
+    ethContext = ethProtocolManager.ethContext();
+    syncState = new SyncState(protocolContext.getBlockchain(), ethContext.getEthPeers());
+
+    ethTaskTimer = NoOpMetricsSystem.NO_OP_LABELLED_TIMER;
+  }
+
+  private FastSyncChainDownloader<?> downloader(
+      final SynchronizerConfiguration syncConfig, final long pivotBlockNumber) {
+    return new FastSyncChainDownloader<>(
+        syncConfig,
+        protocolSchedule,
+        protocolContext,
+        ethContext,
+        syncState,
+        ethTaskTimer,
+        otherBlockchain.getBlockHeader(pivotBlockNumber).get());
+  }
+
+  @Test
+  public void shouldSyncToPivotBlockInMultipleSegments() {
+    otherBlockchainSetup.importFirstBlocks(30);
+
+    final RespondingEthPeer peer =
+        EthProtocolManagerTestUtil.createPeer(ethProtocolManager, otherBlockchain);
+    final Responder responder = RespondingEthPeer.blockchainResponder(otherBlockchain);
+
+    final SynchronizerConfiguration syncConfig =
+        SynchronizerConfiguration.builder()
+            .downloaderChainSegmentSize(5)
+            .downloaderHeadersRequestSize(3)
+            .build()
+            .validated(localBlockchain);
+    final long pivotBlockNumber = 25;
+    final FastSyncChainDownloader<?> downloader = downloader(syncConfig, pivotBlockNumber);
+    final CompletableFuture<Void> result = downloader.start();
+
+    peer.respondWhile(responder, () -> !result.isDone());
+
+    assertThat(result).isCompleted();
+    assertThat(localBlockchain.getChainHeadBlockNumber()).isEqualTo(pivotBlockNumber);
+    assertThat(localBlockchain.getChainHeadHeader())
+        .isEqualTo(otherBlockchain.getBlockHeader(pivotBlockNumber).get());
+  }
+
+  @Test
+  public void shouldSyncToPivotBlockInSingleSegment() {
+    otherBlockchainSetup.importFirstBlocks(30);
+
+    final RespondingEthPeer peer =
+        EthProtocolManagerTestUtil.createPeer(ethProtocolManager, otherBlockchain);
+    final Responder responder = RespondingEthPeer.blockchainResponder(otherBlockchain);
+
+    final long pivotBlockNumber = 5;
+    final SynchronizerConfiguration syncConfig =
+        SynchronizerConfiguration.builder().build().validated(localBlockchain);
+    final FastSyncChainDownloader<?> downloader = downloader(syncConfig, pivotBlockNumber);
+    final CompletableFuture<Void> result = downloader.start();
+
+    peer.respondWhile(responder, () -> !result.isDone());
+
+    assertThat(result).isCompleted();
+    assertThat(localBlockchain.getChainHeadBlockNumber()).isEqualTo(pivotBlockNumber);
+    assertThat(localBlockchain.getChainHeadHeader())
+        .isEqualTo(otherBlockchain.getBlockHeader(pivotBlockNumber).get());
+  }
+
+  @Test
+  public void recoversFromSyncTargetDisconnect() {
+    final BlockchainSetupUtil<Void> shorterChainUtil = BlockchainSetupUtil.forTesting();
+    final MutableBlockchain shorterChain = shorterChainUtil.getBlockchain();
+
+    otherBlockchainSetup.importFirstBlocks(30);
+    shorterChainUtil.importFirstBlocks(28);
+
+    final RespondingEthPeer bestPeer =
+        EthProtocolManagerTestUtil.createPeer(ethProtocolManager, otherBlockchain);
+    final Responder bestResponder = RespondingEthPeer.blockchainResponder(otherBlockchain);
+    final RespondingEthPeer secondBestPeer =
+        EthProtocolManagerTestUtil.createPeer(ethProtocolManager, shorterChain);
+    final Responder shorterResponder = RespondingEthPeer.blockchainResponder(shorterChain);
+
+    final SynchronizerConfiguration syncConfig =
+        SynchronizerConfiguration.builder()
+            .downloaderChainSegmentSize(5)
+            .downloaderHeadersRequestSize(3)
+            .build()
+            .validated(localBlockchain);
+    final long pivotBlockNumber = 25;
+    final FastSyncChainDownloader<?> downloader = downloader(syncConfig, pivotBlockNumber);
+    final CompletableFuture<Void> result = downloader.start();
+
+    while (localBlockchain.getChainHeadBlockNumber() < 15) {
+      bestPeer.respond(bestResponder);
+      secondBestPeer.respond(shorterResponder);
+    }
+
+    assertThat(localBlockchain.getChainHeadBlockNumber()).isEqualTo(15);
+    assertThat(result).isNotCompleted();
+
+    ethProtocolManager.handleDisconnect(bestPeer.getPeerConnection(), TOO_MANY_PEERS, true);
+
+    secondBestPeer.respondWhile(shorterResponder, () -> !result.isDone());
+
+    assertThat(result).isCompleted();
+    assertThat(localBlockchain.getChainHeadBlockNumber()).isEqualTo(pivotBlockNumber);
+    assertThat(localBlockchain.getChainHeadHeader())
+        .isEqualTo(otherBlockchain.getBlockHeader(pivotBlockNumber).get());
+  }
+}