Validate streaming writer chunk type in testing

test/__mocks__/node-polyfill-web-streams.js

@@ -0,0 +1,21 @@
+// Use CJS format for represent next/dist/compiled/node-polyfill-web-streams.js
+
+const {
+  WritableStreamDefaultWriter,
+  ReadableStream,
+  TransformStream,
+} = require('next/dist/compiled/web-streams-polyfill')
+
+const OriginWritableStreamWrite = WritableStreamDefaultWriter.prototype.write
+
+// Override writable stream write method to validate chunk type.
+// Currently CF workers only allow to write the encoded chunk in Uint8Array format.
+WritableStreamDefaultWriter.prototype.write = function (chunk) {
+  if (!(chunk instanceof Uint8Array)) {
+    throw new Error('Writing non Uint8Array chunk in streaming is not allowed')
+  }
+  return OriginWritableStreamWrite.call(this, chunk)
+}
+
+global.ReadableStream = ReadableStream
+global.TransformStream = TransformStream

test/lib/mocks-require-hook.js

@@ -0,0 +1,24 @@
+const mod = require('module')
+
+const hookPropertyMap = new Map([
+  [
+    /node-polyfill-web-streams/,
+    require.resolve('../__mocks__/node-polyfill-web-streams.js'),
+  ],
+])
+
+function matchModule(request) {
+  for (const [key, value] of hookPropertyMap) {
+    if (key.test(request)) {
+      return value
+    }
+  }
+  return null
+}
+
+const resolveFilename = mod._resolveFilename
+mod._resolveFilename = function (request, parent, isMain, options) {
+  const hookResolved = matchModule(request) // hookPropertyMap.get(request)
+  if (hookResolved) request = hookResolved
+  return resolveFilename.call(mod, request, parent, isMain, options)
+}

test/lib/next-test-utils.js

@@ -31,7 +31,13 @@ export function initNextServerScript(
   return new Promise((resolve, reject) => {
     const instance = spawn(
       'node',
-      [...((opts && opts.nodeArgs) || []), '--no-deprecation', scriptPath],
+      [
+        ...((opts && opts.nodeArgs) || []),
+        '-r',
+        require.resolve('./mocks-require-hook'),
+        '--no-deprecation',
+        scriptPath,
+      ],
       {
         env,
         cwd: opts && opts.cwd,
@@ -147,7 +153,14 @@ export function runNextCommand(argv, options = {}) {
     console.log(`Running command "next ${argv.join(' ')}"`)
     const instance = spawn(
       'node',
-      [...(options.nodeArgs || []), '--no-deprecation', nextBin, ...argv],
+      [
+        ...(options.nodeArgs || []),
+        '-r',
+        require.resolve('./mocks-require-hook'),
+        '--no-deprecation',
+        nextBin,
+        ...argv,
+      ],
       {
         ...options.spawnOptions,
         cwd,
@@ -237,7 +250,14 @@ export function runNextCommandDev(argv, stdOut, opts = {}) {
   return new Promise((resolve, reject) => {
     const instance = spawn(
       'node',
-      [...nodeArgs, '--no-deprecation', nextBin, ...argv],
+      [
+        ...nodeArgs,
+        '-r',
+        require.resolve('./mocks-require-hook'),
+        '--no-deprecation',
+        nextBin,
+        ...argv,
+      ],
       {
         cwd,
         env,