5 files changed, 45 insertions, 23 deletions
diff --git a/test/parallel/test-process-euid-egid.js b/test/parallel/test-process-euid-egid.js
index 5639163bf3..b9e0630dab 100644
--- a/test/parallel/test-process-euid-egid.js
+++ b/test/parallel/test-process-euid-egid.js
@@ -3,16 +3,17 @@
 const common = require('../common');
 const assert = require('assert');
 
-if (common.isWindows || !common.isMainThread) {
-  if (common.isMainThread) {
-    assert.strictEqual(process.geteuid, undefined);
-    assert.strictEqual(process.getegid, undefined);
-  }
+if (common.isWindows) {
+  assert.strictEqual(process.geteuid, undefined);
+  assert.strictEqual(process.getegid, undefined);
   assert.strictEqual(process.seteuid, undefined);
   assert.strictEqual(process.setegid, undefined);
   return;
 }
 
+if (!common.isMainThread)
+  return;
+
 assert.throws(() => {
   process.seteuid({});
 }, {
diff --git a/test/parallel/test-process-initgroups.js b/test/parallel/test-process-initgroups.js
index 49b8833f61..f5e839b1d2 100644
--- a/test/parallel/test-process-initgroups.js
+++ b/test/parallel/test-process-initgroups.js
@@ -2,11 +2,14 @@
 const common = require('../common');
 const assert = require('assert');
 
-if (common.isWindows || !common.isMainThread) {
+if (common.isWindows) {
   assert.strictEqual(process.initgroups, undefined);
   return;
 }
 
+if (!common.isMainThread)
+  return;
+
 [undefined, null, true, {}, [], () => {}].forEach((val) => {
   assert.throws(
     () => {
diff --git a/test/parallel/test-process-setgroups.js b/test/parallel/test-process-setgroups.js
index a85d668316..74de3e7a25 100644
--- a/test/parallel/test-process-setgroups.js
+++ b/test/parallel/test-process-setgroups.js
@@ -2,11 +2,14 @@
 const common = require('../common');
 const assert = require('assert');
 
-if (common.isWindows || !common.isMainThread) {
+if (common.isWindows) {
   assert.strictEqual(process.setgroups, undefined);
   return;
 }
 
+if (!common.isMainThread)
+  return;
+
 assert.throws(
   () => {
     process.setgroups();
diff --git a/test/parallel/test-process-uid-gid.js b/test/parallel/test-process-uid-gid.js
index 456cba7f4d..49086792b9 100644
--- a/test/parallel/test-process-uid-gid.js
+++ b/test/parallel/test-process-uid-gid.js
@@ -24,17 +24,18 @@ const common = require('../common');
 
 const assert = require('assert');
 
-if (common.isWindows || !common.isMainThread) {
-  // uid/gid functions are POSIX only, setters are main-thread only.
-  if (common.isMainThread) {
-    assert.strictEqual(process.getuid, undefined);
-    assert.strictEqual(process.getgid, undefined);
-  }
+if (common.isWindows) {
+  // uid/gid functions are POSIX only.
+  assert.strictEqual(process.getuid, undefined);
+  assert.strictEqual(process.getgid, undefined);
   assert.strictEqual(process.setuid, undefined);
   assert.strictEqual(process.setgid, undefined);
   return;
 }
 
+if (!common.isMainThread)
+  return;
+
 assert.throws(() => {
   process.setuid({});
 }, {
diff --git a/test/parallel/test-worker-unsupported-things.js b/test/parallel/test-worker-unsupported-things.js
index 66b10ad157..cc9eec4af6 100644
--- a/test/parallel/test-worker-unsupported-things.js
+++ b/test/parallel/test-worker-unsupported-things.js
@@ -1,9 +1,12 @@
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const { Worker, isMainThread, parentPort } = require('worker_threads');
+const { Worker, parentPort } = require('worker_threads');
 
-if (isMainThread) {
+// Do not use isMainThread so that this test itself can be run inside a Worker.
+if (!process.env.HAS_STARTED_WORKER) {
+  process.env.HAS_STARTED_WORKER = 1;
+  process.env.NODE_CHANNEL_FD = 'foo'; // Make worker think it has IPC.
   const w = new Worker(__filename);
   w.on('message', common.mustCall((message) => {
     assert.strictEqual(message, true);
@@ -21,14 +24,25 @@ if (isMainThread) {
     assert.strictEqual(process.debugPort, before);
   }
 
-  assert.strictEqual('abort' in process, false);
-  assert.strictEqual('chdir' in process, false);
-  assert.strictEqual('setuid' in process, false);
-  assert.strictEqual('seteuid' in process, false);
-  assert.strictEqual('setgid' in process, false);
-  assert.strictEqual('setegid' in process, false);
-  assert.strictEqual('setgroups' in process, false);
-  assert.strictEqual('initgroups' in process, false);
+  const stubs = ['abort', 'chdir', 'send', 'disconnect'];
+
+  if (!common.isWindows) {
+    stubs.push('setuid', 'seteuid', 'setgid',
+               'setegid', 'setgroups', 'initgroups');
+  }
+
+  stubs.forEach((fn) => {
+    assert.strictEqual(process[fn].disabled, true);
+    assert.throws(() => {
+      process[fn]();
+    }, { code: 'ERR_WORKER_UNSUPPORTED_OPERATION' });
+  });
+
+  ['channel', 'connected'].forEach((fn) => {
+    assert.throws(() => {
+      process[fn];
+    }, { code: 'ERR_WORKER_UNSUPPORTED_OPERATION' });
+  });
 
   assert.strictEqual('_startProfilerIdleNotifier' in process, false);
   assert.strictEqual('_stopProfilerIdleNotifier' in process, false);