Charon/docs/plans/TEST_ISOLATION_FINDINGS.md

Test Isolation Findings - Go 1.26.0

Date: 2026-02-16 Investigation: Test failures after Go 1.26.0 upgrade Status: Partial fix committed, further investigation required

Summary

Root Cause Confirmed: Go 1.26.0 upgrade (commit dc40102a) changed timing/signal handling/scheduling behavior.

Key Finding: All 5 failing tests PASS individually but FAIL in full suite → Test isolation issue.

Fixes Completed

✅ Fix #1: TestMain_DefaultStartupGracefulShutdown_Subprocess

• File: backend/cmd/api/main_test.go:287
• Change: Increased SIGTERM timeout from 500ms → 1000ms
• Commit: 62740eb5
• Status: ✅ PASSING individually
• Reason: Go 1.26.0 signal delivery timing changes on Linux

Tests Status Matrix

Test	Individual	Full Suite	Priority	Notes
TestMain_DefaultStartupGracefulShutdown_Subprocess	✅ PASS	❓ Unknown	HIGH	Fixed timeout
TestCredentialService_GetCredentialForDomain_WildcardMatch	✅ PASS	❌ FAIL	HIGH	No code changes needed
TestDeleteCertificate_CreatesBackup	✅ PASS	❌ FAIL	MEDIUM	No code changes needed
TestHeartbeatPoller_ConcurrentSafety	✅ PASS	❌ FAIL	MEDIUM	No code changes needed
TestSecurityService_LogAudit_ChannelFullFallsBackToSyncWrite	✅ PASS	❌ FAIL	MEDIUM	No code changes needed

Test Isolation Issue

Observation: Tests pass when run individually but fail in full suite execution.

Likely Causes:

1. Global State Pollution:

   • Tests modifying shared package-level variables
   • Singleton initialization state persisting between tests
   • Environment variables not being properly cleaned up

2. Database Connection Leaks:

   • SQLite in-memory databases not properly closed
   • GORM connection pool exhaustion
   • WAL mode journal files persisting

3. Goroutine Leaks:

   • Background goroutines from previous tests still running
   • Channels not being closed
   • Context cancellations not propagating

4. Test Execution Order:

   • Tests depending on specific execution order
   • Previous test failures leaving system in bad state
   • Resource cleanup in t.Cleanup() not executing due to panics

5. Race Conditions (Go 1.26.0 Scheduler):

   • Go 1.26.0's more aggressive preemption exposing hidden races
   • Tests making timing assumptions that no longer hold
   • Concurrent test execution causing interference

Investigation Blockers

Current Block: Full test suite hangs or takes excessive time (>2 minutes).

Symptoms:

• go test ./... hangs indefinitely or terminates after 120s timeout
• Cannot get full suite results to see which tests are actually failing
• Cannot collect coverage data from full suite run

Needed:

• Identify which test(s) are causing the hang
• Isolate hanging test(s) and run rest of suite
• Check for infinite loops or deadlocks in test cleanup

Next Steps

Option A: Sequential Investigation (4-6 hours)

1. Run tests package-by-package to identify hanging package
2. Use -timeout 30s flag to catch hanging tests quickly
3. Add goroutine leak detection: go test -race -p 1 ./...
4. Use t.Parallel() marking to understand parallelization issues
5. Add t.Cleanup() verification to catch leak sources

Option B: Quick Workaround (30 minutes)

1. Run tests with -p 1 (no parallelism) to avoid race conditions
2. Increase timeout: -timeout 10m
3. Skip known flaky tests temporarily with t.Skip("Go 1.26.0 isolation issue")
4. Create tracking issue for proper fix

Option C: Rollback Go Version (NOT RECOMMENDED)

• Revert to Go 1.25.7
• Loses security fixes
• Kicks can down road

Recommendation

Hybrid Approach:

1. Immediate (now): Run tests with -p 1 -timeout 5m to force sequential execution
2. Short-term (today): Identify hanging tests and skip with tracking issue
3. Long-term (this week): Fix test isolation properly with cleanup audits

Why: Unblocks CI immediately while preserving investigation path.

Commands for Investigation

# Run sequentially with timeout
go test -p 1 -timeout 5m ./...

# Find hanging test packages
for pkg in $(go list ./...); do
    echo "Testing $pkg..."
    timeout 30s go test -v "$pkg" || echo "FAILED or TIMEOUT: $pkg"
done

# Check for goroutine leaks
go test -race -p 1 -count=1 ./...

# Run specific packages
go test -v ./cmd/... ./internal/api/... ./internal/services/...

Related Documents

• docs/plans/GO_126_TEST_FAILURES_ANALYSIS.md - Initial analysis
• docs/plans/CI_TEST_FAILURES_DETAILED_REMEDIATION.md - CI failures

Action Items

• Run tests sequentially (-p 1) to check if parallelism is the issue
• Identify hanging test package
• Add timeout flags to test execution script
• Audit all tests for proper t.Cleanup() usage
• Add goroutine leak detection to CI
• Create tracking issue for test isolation fixes