End-to-End (E2E) Testing for Blockchain Synchronization¶

This document describes the comprehensive E2E testing suite for the Fukuii Ethereum Classic client, specifically targeting blockchain synchronization functionality.

Overview¶

The E2E test suite validates the complete blockchain synchronization workflow to ensure that Fukuii can successfully synchronize with peers without issues in P2P handshake, block exchange, or storage operations.

Test Suites¶

1. E2ESyncSpec - Regular Synchronization Tests¶

Location: src/it/scala/com/chipprbots/ethereum/sync/E2ESyncSpec.scala

Purpose: Validates regular blockchain synchronization between peers.

Test Categories:

P2P Handshake¶

Successful connection establishment between two peers
Multiple peer connections simultaneously
Handshake timeout recovery

Block Exchange¶

Block exchange between two peers
Block exchange with multiple peers
Incremental block propagation
Large batch block handling

Storage Integrity¶

Consistent storage during synchronization
Blockchain reorganization handling
Block data integrity verification
Block persistence across restarts

Error Handling and Recovery¶

Recovery from peer disconnection
Handling peers at different block heights
Partial block download recovery

Bi-directional Synchronization¶

Mutual block propagation
Block propagation across peer network

Tags: IntegrationTest, SyncTest, NetworkTest, DatabaseTest, SlowTest

Execution Time: 10-30 minutes (depending on configuration)

2. E2EFastSyncSpec - Fast Sync Tests¶

Location: src/it/scala/com/chipprbots/ethereum/sync/E2EFastSyncSpec.scala

Purpose: Validates fast sync protocol for efficient initial blockchain synchronization.

Test Categories:

Header Synchronization¶

Blockchain header download without state
Pivot block selection and validation

State Synchronization¶

State download at pivot block
Complex account structure handling
State validation against state root

Multi-Peer State Download¶

State synchronization from multiple peers
Recovery from incomplete state downloads
Peer disconnection during state download

Chain Integrity¶

Chain continuity verification
Total difficulty calculation
Transition from fast sync to regular sync

Tags: IntegrationTest, SyncTest, StateTest, NetworkTest, DatabaseTest, SlowTest

Execution Time: 15-40 minutes (depending on configuration)

3. E2EHandshakeSpec - P2P Handshake Tests¶

Location: src/it/scala/com/chipprbots/ethereum/network/E2EHandshakeSpec.scala

Purpose: Validates P2P connection establishment and handshake protocol.

Test Categories:

RLPx Connection Establishment¶

Basic RLPx connection between peers
Multiple simultaneous connections
Bidirectional connection attempts

Ethereum Protocol Handshake¶

Node status exchange
Protocol version compatibility
Genesis block hash verification

Fork Block Exchange¶

Fork block validation during handshake
Compatible fork configuration handling

Handshake Timeout Handling¶

Slow handshake response handling
Failed handshake retry logic

Peer Discovery and Handshake¶

Handshake with discovered peers
Connection maintenance after handshake

Handshake with Chain State¶

Handshake with peers at different heights
Handshake with peers at genesis
Total difficulty exchange

Concurrent Handshakes¶

Multiple concurrent handshake handling
Handshakes during active sync

Error Recovery¶

Recovery from handshake failures
Incompatible parameter handling

Tags: IntegrationTest, NetworkTest, SlowTest

Execution Time: 10-25 minutes (depending on configuration)

Running the Tests¶

Run All E2E Tests¶

sbt "IntegrationTest / testOnly *E2E*"

Run Specific Test Suite¶

# Run regular sync E2E tests
sbt "IntegrationTest / testOnly *E2ESyncSpec"

# Run fast sync E2E tests
sbt "IntegrationTest / testOnly *E2EFastSyncSpec"

# Run handshake E2E tests
sbt "IntegrationTest / testOnly *E2EHandshakeSpec"

Run Specific Test¶

# Run a specific test by pattern
sbt "IntegrationTest / testOnly *E2ESyncSpec -- -z 'block exchange'"

Run Tests with Tags¶

# Run only NetworkTest tagged tests
sbt "IntegrationTest / testOnly -- -n NetworkTest"

# Run tests excluding SlowTest
sbt "IntegrationTest / testOnly *E2E* -- -l SlowTest"

Test Infrastructure¶

FakePeer Framework¶

The E2E tests utilize the existing FakePeer framework from sync.util package:

RegularSyncItSpecUtils.FakePeer: For regular sync testing
FastSyncItSpecUtils.FakePeer: For fast sync testing

Resource Management¶

Tests use Cats Effect Resource for proper lifecycle management:

customTestCaseResourceM(FakePeer.start2FakePeersRes()) { case (peer1, peer2) =>
  // Test implementation
}

This ensures: - Proper peer initialization - Cleanup of resources after test - No resource leaks between tests

Test Configuration¶

Tests use: - TestSyncConfig: Test-specific sync configuration - In-memory storage: RocksDB with temporary directories - Isolated actor systems: Separate for each peer - Configurable metrics: Prometheus metrics for monitoring

Success Criteria¶

P2P Handshake¶

✅ Successful RLPx connection establishment
✅ Protocol version negotiation
✅ Node status exchange
✅ Fork compatibility validation

Block Exchange¶

✅ Correct block propagation between peers
✅ Block validation during exchange
✅ Handling of large block batches
✅ Recovery from partial downloads

Storage Integrity¶

✅ Consistent blockchain state across peers
✅ Correct total difficulty calculation
✅ Valid chain continuity
✅ Proper block persistence

Fast Sync¶

✅ Correct pivot block selection
✅ Complete state download
✅ State root validation
✅ Smooth transition to regular sync

Known Limitations¶

Test Duration: Some tests are marked as SlowTest due to blockchain operations
Resource Usage: Multiple peers require significant memory (configured in .jvmopts)
Non-deterministic Timing: Some tests use delays for network operations

Troubleshooting¶

Test Timeout¶

If tests timeout: - Increase timeout in test configuration - Check available system resources - Review logs for stuck operations

Connection Issues¶

If peers fail to connect: - Verify network configuration - Check for port conflicts - Review handshaker logs

Storage Issues¶

If storage tests fail: - Ensure sufficient disk space in /tmp - Check RocksDB configuration - Verify cleanup between tests

Integration with CI/CD¶

GitHub Actions¶

E2E tests are executed in the CI pipeline:

- name: Run E2E Integration Tests
  run: sbt "IntegrationTest / testOnly *E2E*"
  timeout-minutes: 45

Nightly Builds¶

Comprehensive E2E tests run in nightly builds with extended timeouts.

Metrics and Monitoring¶

Tests collect the following metrics:

Connection establishment time
Block download rate
State download progress
Handshake success/failure rate
Storage operation latency

Future Enhancements¶

Network Simulation: Add network latency and packet loss simulation
Byzantine Behavior: Test handling of malicious peers
Large-Scale Testing: Increase peer count for network testing
Performance Benchmarks: Add performance metrics collection
Chaos Testing: Random peer failures and recoveries

Contributing¶

When adding new E2E tests:

Follow existing test structure and patterns
Use appropriate ScalaTest tags
Ensure proper resource cleanup
Document expected behavior
Consider test execution time

References¶

Revision History¶

Date	Version	Changes	Author
2025-11-16	1.0	Initial E2E test suite implementation	GitHub Copilot

Maintained by: Chippr Robotics Engineering Team
Last Updated: November 16, 2025