feat(node/e2e-tests): add restart tests

[theochap]

Description

This PR adds restart tests for the kona node

[claude]

Claude finished @theochap's task —— View job

---

Code Review Complete

I've reviewed the restart tests implementation and have the following feedback:

Code Quality & Best Practices ✅

• Clean, well-structured test following Go testing conventions
• Good use of goroutines with sync.WaitGroup for parallel testing
• Proper error handling with t.Require() assertions
• Clear variable naming and logical flow
• Consistent with existing test patterns in the codebase

Test Logic & Coverage ✅

The restart test (TestRestartSync) provides comprehensive coverage:

• Tests multiple validator nodes in parallel
• Verifies node shutdown (stops service, checks disconnection, validates RPC errors)
• Tests restart recovery (starts service, reconnects to sequencer)
• Validates synchronization after restart (checks LocalSafe/LocalUnsafe matching)
• Confirms peer connectivity post-restart

Potential Issues ⚠️

1. Hard-coded timeout: Line 53 uses time.Sleep(2 * time.Minute) which could make tests slow. Consider making this configurable or reducing for CI environments.

2. Race condition potential: The peer disconnection check (lines 41-44) happens immediately after node.Stop(). There might be a brief race condition where the sequencer hasn't yet updated its peer list.

3. Limited error context: Line 51 only checks that an RPC call returns an error but doesn't validate the specific error type. A connection refused error vs other errors could be distinguished.

Comparison with Existing Code ✅

The restart test follows the same pattern as conn_drop_test.go:

• Uses identical imports and test structure
• Leverages same helper functions (GetNodeRPCEndpoint, peer management)
• Consistent error handling and logging patterns

Minor Improvements

• Consider extracting the 2-minute timeout as a constant
• Could add a brief retry/wait loop for peer disconnection verification instead of assuming immediate effect

Dependency Updates ✅

The go.mod changes look appropriate:

• Optimism dependency update to newer version
• Go version update to 1.24.3
• No suspicious or unnecessary additions

Security & Performance ✅

• No security concerns identified
• Performance impact is reasonable for integration tests
• Proper resource cleanup with goroutines and WaitGroup

Overall Assessment ✅

This is a well-implemented test that provides valuable coverage for node restart scenarios. The code is clean, follows established patterns, and tests an important failure/recovery scenario. The minor timing issues mentioned are typical for integration tests and don't significantly impact the test's value.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.1%. Comparing base (ac92895) to head (2b07643).
⚠️ Report is 18 commits behind head on theo/conn-drop-test.
✅ All tests successful. No failed tests found.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.