OpenNext SSR Test

This directory contains tests for running actual OpenNext Cloudflare bundled output in workerd. The test verifies that workerd can correctly execute Next.js SSR applications built with the @opennextjs/cloudflare adapter.

Files

• opennext-ssr-test.js - Test cases for API routes, SSR pages, streaming, RSC, etc.
• opennext-ssr-test.wd-test - workerd test configuration
• src/ - Next.js application source files (JavaScript/JSX)

Running the Test

The worker is automatically generated from source before the test runs:

bazel test //src/workerd/api/tests/opennextjs:opennext-ssr-test@

Note: This test is Linux-only (target_compatible_with = ["@platforms//os:linux"]) due to the reliance on the Next.js/OpenNext build toolchain.

How It Works

1. opennextjs-build: Runs @opennextjs/cloudflare build to compile the Next.js app and generate the OpenNext worker in .open-next/
2. opennextjs-worker: Runs wrangler deploy --dry-run --outdir=dist to bundle the worker
3. The output dist/worker.js is copied to opennext-ssr-worker.js
4. The test runner loads the worker and executes test cases against it

Compatibility Flags

The test harness uses nodejs_compat_v2 along with several additional Node.js module flags required (and defined in src/wrangler.jsonc) by the OpenNext runtime. These flags are configured in:

• src/wrangler.jsonc - For the wrangler build
• opennext-ssr-test.wd-test - For the workerd test runtime

Key flags include:

• nodejs_compat_v2 - Enables Node.js compatibility layer (required due to test harness using oldest & latest compatibility dates)
• enable_nodejs_os_module - Required for node:os module
• enable_nodejs_fs_module - Required for node:fs module
• enable_nodejs_vm_module - Required for node:vm module
• enable_nodejs_http_modules - Required for node:http modules

Why JavaScript Instead of TypeScript?

The Next.js app uses JavaScript (.js/.jsx) instead of TypeScript because Next.js automatically modifies tsconfig.json during builds. This conflicts with Bazel's sandbox, which treats source files as read-only. Using JavaScript with jsconfig.json avoids this issue.

Build Sandbox Note

The opennextjs-build target uses execution_requirements = {"no-sandbox": "1"} because Next.js needs to write various files during the build process (caches, generated files, etc.) which is incompatible with Bazel's default read-only sandbox.