Local Reproduction Guide

Match CI Job Mode

Dev-mode failures: use pnpm test-dev-turbo or pnpm test-dev-webpack based on job mode.
Start-mode failures: use pnpm test-start-turbo or pnpm test-start-webpack.

Match CI Environment Variables

Read the "Job Environment Variables" section in index.md and mirror them locally. Key variables:

IS_WEBPACK_TEST=1 — forces webpack mode (turbopack is default locally).
NEXT_SKIP_ISOLATE=1 — skips package isolation; never use when verifying module resolution or build-time compilation fixes.
Feature flags like __NEXT_USE_NODE_STREAMS=true, __NEXT_CACHE_COMPONENTS=true change DefinePlugin replacements.

Example: a failure in "test node streams prod" needs:

bash

IS_WEBPACK_TEST=1 __NEXT_USE_NODE_STREAMS=true __NEXT_CACHE_COMPONENTS=true NEXT_TEST_MODE=start

Isolation Rule

When validating module-resolution, entrypoint-export, or internal require-path fixes, rerun without NEXT_SKIP_ISOLATE=1.

One-Run Log Analysis

Capture once, analyze multiple times:

bash

HEADLESS=true pnpm test-dev-turbo test/path/to/test.ts > /tmp/test-output.log 2>&1
grep "●" /tmp/test-output.log
grep -A5 "Error:" /tmp/test-output.log
tail -5 /tmp/test-output.log