diff --git a/test/parallel/test-child-process-fork-args.js b/test/parallel/test-child-process-fork-args.js
index 7c86616f3750c6..f2f5689d64d6ba 100644
--- a/test/parallel/test-child-process-fork-args.js
+++ b/test/parallel/test-child-process-fork-args.js
@@ -64,7 +64,7 @@ const expectedEnv = { foo: 'bar' };
 
   argsLists.forEach((args) => {
     const cp = fork(fixtures.path('child-process-echo-options.js'), args, {
-      env: Object.assign({}, process.env, expectedEnv)
+      env: { ...process.env, ...expectedEnv }
     });
 
     cp.on(
diff --git a/test/parallel/test-child-process-fork-exec-path.js b/test/parallel/test-child-process-fork-exec-path.js
index 6a99c5a8f55d62..38adfd72de4298 100644
--- a/test/parallel/test-child-process-fork-exec-path.js
+++ b/test/parallel/test-child-process-fork-exec-path.js
@@ -51,7 +51,7 @@ assert.strictEqual(fs.existsSync(copyPath), false);
 fs.copyFileSync(nodePath, copyPath, fs.constants.COPYFILE_FICLONE);
 fs.chmodSync(copyPath, '0755');
 
-const envCopy = Object.assign({}, process.env, { 'FORK': 'true' });
+const envCopy = { ...process.env, FORK: 'true' };
 const child = fork(__filename, { execPath: copyPath, env: envCopy });
 child.on('message', common.mustCall(function(recv) {
   assert.deepStrictEqual(recv, msg);